diff --git a/.changes/unreleased/BUG FIXES-20230210-092136.yaml b/.changes/unreleased/BUG FIXES-20230210-092136.yaml
new file mode 100644
index 000000000..9d237ac30
--- /dev/null
+++ b/.changes/unreleased/BUG FIXES-20230210-092136.yaml	
@@ -0,0 +1,5 @@
+kind: BUG FIXES
+body: 'resource: Prevented nested attribute and block plan modifications from being undone'
+time: 2023-02-10T09:21:36.848573-05:00
+custom:
+  Issue: "669"
diff --git a/internal/fwserver/attribute_plan_modification.go b/internal/fwserver/attribute_plan_modification.go
index 1afbf2c9a..01d876a2e 100644
--- a/internal/fwserver/attribute_plan_modification.go
+++ b/internal/fwserver/attribute_plan_modification.go
@@ -135,7 +135,9 @@ func AttributeModifyPlan(ctx context.Context, a fwschema.Attribute, req ModifyAt
 			return
 		}
 
-		planList, diags := coerceListValue(ctx, req.AttributePath, req.AttributePlan)
+		// Use response as the planned value may have been modified with list
+		// plan modifiers.
+		planList, diags := coerceListValue(ctx, req.AttributePath, resp.AttributePlan)
 
 		resp.Diagnostics.Append(diags...)
 
@@ -220,7 +222,9 @@ func AttributeModifyPlan(ctx context.Context, a fwschema.Attribute, req ModifyAt
 			return
 		}
 
-		planSet, diags := coerceSetValue(ctx, req.AttributePath, req.AttributePlan)
+		// Use response as the planned value may have been modified with set
+		// plan modifiers.
+		planSet, diags := coerceSetValue(ctx, req.AttributePath, resp.AttributePlan)
 
 		resp.Diagnostics.Append(diags...)
 
@@ -305,7 +309,9 @@ func AttributeModifyPlan(ctx context.Context, a fwschema.Attribute, req ModifyAt
 			return
 		}
 
-		planMap, diags := coerceMapValue(ctx, req.AttributePath, req.AttributePlan)
+		// Use response as the planned value may have been modified with map
+		// plan modifiers.
+		planMap, diags := coerceMapValue(ctx, req.AttributePath, resp.AttributePlan)
 
 		resp.Diagnostics.Append(diags...)
 
@@ -390,7 +396,9 @@ func AttributeModifyPlan(ctx context.Context, a fwschema.Attribute, req ModifyAt
 			return
 		}
 
-		planObject, diags := coerceObjectValue(ctx, req.AttributePath, req.AttributePlan)
+		// Use response as the planned value may have been modified with object
+		// plan modifiers.
+		planObject, diags := coerceObjectValue(ctx, req.AttributePath, resp.AttributePlan)
 
 		resp.Diagnostics.Append(diags...)
 
diff --git a/internal/fwserver/attribute_plan_modification_test.go b/internal/fwserver/attribute_plan_modification_test.go
index 6c206e63e..de4a9aec3 100644
--- a/internal/fwserver/attribute_plan_modification_test.go
+++ b/internal/fwserver/attribute_plan_modification_test.go
@@ -20,7 +20,11 @@ import (
 	"github.com/hashicorp/terraform-plugin-framework/internal/testing/testschema"
 	"github.com/hashicorp/terraform-plugin-framework/path"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/listplanmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/mapplanmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/objectplanmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/setplanmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/stringplanmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
 	"github.com/hashicorp/terraform-plugin-framework/types"
@@ -216,6 +220,75 @@ func TestAttributeModifyPlan(t *testing.T) {
 				Private: testProviderData,
 			},
 		},
+		"attribute-list-nested-usestateforunknown": {
+			attribute: testschema.NestedAttributeWithListPlanModifiers{
+				NestedObject: testschema.NestedAttributeObject{
+					Attributes: map[string]fwschema.Attribute{
+						"nested_computed": testschema.Attribute{
+							Type:     types.StringType,
+							Computed: true,
+						},
+					},
+				},
+				Computed: true,
+				PlanModifiers: []planmodifier.List{
+					listplanmodifier.UseStateForUnknown(),
+				},
+			},
+			req: ModifyAttributePlanRequest{
+				AttributeConfig: types.ListNull(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributePath: path.Root("test"),
+				AttributePlan: types.ListUnknown(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributeState: types.ListValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					[]attr.Value{
+						types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+			expectedResp: ModifyAttributePlanResponse{
+				AttributePlan: types.ListValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					[]attr.Value{
+						types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+		},
 		"attribute-set-nested-private": {
 			attribute: testschema.NestedAttributeWithSetPlanModifiers{
 				NestedObject: testschema.NestedAttributeObject{
@@ -310,6 +383,75 @@ func TestAttributeModifyPlan(t *testing.T) {
 			},
 		},
 		"attribute-set-nested-usestateforunknown": {
+			attribute: testschema.NestedAttributeWithSetPlanModifiers{
+				NestedObject: testschema.NestedAttributeObject{
+					Attributes: map[string]fwschema.Attribute{
+						"nested_computed": testschema.Attribute{
+							Type:     types.StringType,
+							Computed: true,
+						},
+					},
+				},
+				Computed: true,
+				PlanModifiers: []planmodifier.Set{
+					setplanmodifier.UseStateForUnknown(),
+				},
+			},
+			req: ModifyAttributePlanRequest{
+				AttributeConfig: types.SetNull(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributePath: path.Root("test"),
+				AttributePlan: types.SetUnknown(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributeState: types.SetValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					[]attr.Value{
+						types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+			expectedResp: ModifyAttributePlanResponse{
+				AttributePlan: types.SetValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					[]attr.Value{
+						types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+		},
+		"attribute-set-nested-nested-usestateforunknown": {
 			attribute: testschema.NestedAttribute{
 				NestedObject: testschema.NestedAttributeObject{
 					Attributes: map[string]fwschema.Attribute{
@@ -547,6 +689,75 @@ func TestAttributeModifyPlan(t *testing.T) {
 				Private: testProviderData,
 			},
 		},
+		"attribute-map-nested-usestateforunknown": {
+			attribute: testschema.NestedAttributeWithMapPlanModifiers{
+				NestedObject: testschema.NestedAttributeObject{
+					Attributes: map[string]fwschema.Attribute{
+						"nested_computed": testschema.Attribute{
+							Type:     types.StringType,
+							Computed: true,
+						},
+					},
+				},
+				Computed: true,
+				PlanModifiers: []planmodifier.Map{
+					mapplanmodifier.UseStateForUnknown(),
+				},
+			},
+			req: ModifyAttributePlanRequest{
+				AttributeConfig: types.MapNull(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributePath: path.Root("test"),
+				AttributePlan: types.MapUnknown(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributeState: types.MapValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					map[string]attr.Value{
+						"key1": types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+			expectedResp: ModifyAttributePlanResponse{
+				AttributePlan: types.MapValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					map[string]attr.Value{
+						"key1": types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+		},
 		"attribute-single-nested-private": {
 			attribute: testschema.NestedAttributeWithObjectPlanModifiers{
 				NestedObject: testschema.NestedAttributeObject{
@@ -604,6 +815,53 @@ func TestAttributeModifyPlan(t *testing.T) {
 				Private: testProviderData,
 			},
 		},
+		"attribute-single-nested-usestateforunknown": {
+			attribute: testschema.NestedAttributeWithObjectPlanModifiers{
+				NestedObject: testschema.NestedAttributeObject{
+					Attributes: map[string]fwschema.Attribute{
+						"nested_computed": testschema.Attribute{
+							Type:     types.StringType,
+							Computed: true,
+						},
+					},
+				},
+				Computed: true,
+				PlanModifiers: []planmodifier.Object{
+					objectplanmodifier.UseStateForUnknown(),
+				},
+			},
+			req: ModifyAttributePlanRequest{
+				AttributeConfig: types.ObjectNull(
+					map[string]attr.Type{
+						"nested_computed": types.StringType,
+					},
+				),
+				AttributePath: path.Root("test"),
+				AttributePlan: types.ObjectUnknown(
+					map[string]attr.Type{
+						"nested_computed": types.StringType,
+					},
+				),
+				AttributeState: types.ObjectValueMust(
+					map[string]attr.Type{
+						"nested_computed": types.StringType,
+					},
+					map[string]attr.Value{
+						"nested_computed": types.StringValue("statevalue1"),
+					},
+				),
+			},
+			expectedResp: ModifyAttributePlanResponse{
+				AttributePlan: types.ObjectValueMust(
+					map[string]attr.Type{
+						"nested_computed": types.StringType,
+					},
+					map[string]attr.Value{
+						"nested_computed": types.StringValue("statevalue1"),
+					},
+				),
+			},
+		},
 		"requires-replacement": {
 			attribute: testschema.AttributeWithStringPlanModifiers{
 				Required: true,
diff --git a/internal/fwserver/block_plan_modification.go b/internal/fwserver/block_plan_modification.go
index 91dafc524..5ff5955d9 100644
--- a/internal/fwserver/block_plan_modification.go
+++ b/internal/fwserver/block_plan_modification.go
@@ -55,7 +55,9 @@ func BlockModifyPlan(ctx context.Context, b fwschema.Block, req ModifyAttributeP
 			return
 		}
 
-		planList, diags := coerceListValue(ctx, req.AttributePath, req.AttributePlan)
+		// Use response as the planned value may have been modified with list
+		// plan modifiers.
+		planList, diags := coerceListValue(ctx, req.AttributePath, resp.AttributePlan)
 
 		resp.Diagnostics.Append(diags...)
 
@@ -140,7 +142,9 @@ func BlockModifyPlan(ctx context.Context, b fwschema.Block, req ModifyAttributeP
 			return
 		}
 
-		planSet, diags := coerceSetValue(ctx, req.AttributePath, req.AttributePlan)
+		// Use response as the planned value may have been modified with set
+		// plan modifiers.
+		planSet, diags := coerceSetValue(ctx, req.AttributePath, resp.AttributePlan)
 
 		resp.Diagnostics.Append(diags...)
 
@@ -225,7 +229,9 @@ func BlockModifyPlan(ctx context.Context, b fwschema.Block, req ModifyAttributeP
 			return
 		}
 
-		planObject, diags := coerceObjectValue(ctx, req.AttributePath, req.AttributePlan)
+		// Use response as the planned value may have been modified with object
+		// plan modifiers.
+		planObject, diags := coerceObjectValue(ctx, req.AttributePath, resp.AttributePlan)
 
 		resp.Diagnostics.Append(diags...)
 
diff --git a/internal/fwserver/block_plan_modification_test.go b/internal/fwserver/block_plan_modification_test.go
index e0477622c..5b58e2a82 100644
--- a/internal/fwserver/block_plan_modification_test.go
+++ b/internal/fwserver/block_plan_modification_test.go
@@ -17,7 +17,10 @@ import (
 	"github.com/hashicorp/terraform-plugin-framework/internal/testing/testplanmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/internal/testing/testschema"
 	"github.com/hashicorp/terraform-plugin-framework/path"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/listplanmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/objectplanmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/setplanmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/stringplanmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
 	"github.com/hashicorp/terraform-plugin-framework/types"
@@ -578,6 +581,72 @@ func TestBlockModifyPlan(t *testing.T) {
 				Private: testProviderData,
 			},
 		},
+		"block-list-usestateforunknown": {
+			block: testschema.BlockWithListPlanModifiers{
+				Attributes: map[string]fwschema.Attribute{
+					"nested_computed": testschema.Attribute{
+						Type:     types.StringType,
+						Computed: true,
+					},
+				},
+				PlanModifiers: []planmodifier.List{
+					listplanmodifier.UseStateForUnknown(),
+				},
+			},
+			req: ModifyAttributePlanRequest{
+				AttributeConfig: types.ListNull(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributePath: path.Root("test"),
+				AttributePlan: types.ListUnknown(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributeState: types.ListValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					[]attr.Value{
+						types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+			expectedResp: ModifyAttributePlanResponse{
+				AttributePlan: types.ListValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					[]attr.Value{
+						types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+		},
 		"block-set-null-plan": {
 			block: testschema.BlockWithSetPlanModifiers{
 				Attributes: map[string]fwschema.Attribute{
@@ -1215,6 +1284,72 @@ func TestBlockModifyPlan(t *testing.T) {
 				),
 			},
 		},
+		"block-set-usestateforunknown": {
+			block: testschema.BlockWithSetPlanModifiers{
+				Attributes: map[string]fwschema.Attribute{
+					"nested_computed": testschema.Attribute{
+						Type:     types.StringType,
+						Computed: true,
+					},
+				},
+				PlanModifiers: []planmodifier.Set{
+					setplanmodifier.UseStateForUnknown(),
+				},
+			},
+			req: ModifyAttributePlanRequest{
+				AttributeConfig: types.SetNull(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributePath: path.Root("test"),
+				AttributePlan: types.SetUnknown(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+				),
+				AttributeState: types.SetValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					[]attr.Value{
+						types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+			expectedResp: ModifyAttributePlanResponse{
+				AttributePlan: types.SetValueMust(
+					types.ObjectType{
+						AttrTypes: map[string]attr.Type{
+							"nested_computed": types.StringType,
+						},
+					},
+					[]attr.Value{
+						types.ObjectValueMust(
+							map[string]attr.Type{
+								"nested_computed": types.StringType,
+							},
+							map[string]attr.Value{
+								"nested_computed": types.StringValue("statevalue1"),
+							},
+						),
+					},
+				),
+			},
+		},
 		"block-single-null-plan": {
 			block: testschema.BlockWithObjectPlanModifiers{
 				Attributes: map[string]fwschema.Attribute{
@@ -1432,6 +1567,50 @@ func TestBlockModifyPlan(t *testing.T) {
 				),
 			},
 		},
+		"block-single-usestateforunknown": {
+			block: testschema.BlockWithObjectPlanModifiers{
+				Attributes: map[string]fwschema.Attribute{
+					"nested_computed": testschema.Attribute{
+						Type:     types.StringType,
+						Computed: true,
+					},
+				},
+				PlanModifiers: []planmodifier.Object{
+					objectplanmodifier.UseStateForUnknown(),
+				},
+			},
+			req: ModifyAttributePlanRequest{
+				AttributeConfig: types.ObjectNull(
+					map[string]attr.Type{
+						"nested_computed": types.StringType,
+					},
+				),
+				AttributePath: path.Root("test"),
+				AttributePlan: types.ObjectUnknown(
+					map[string]attr.Type{
+						"nested_computed": types.StringType,
+					},
+				),
+				AttributeState: types.ObjectValueMust(
+					map[string]attr.Type{
+						"nested_computed": types.StringType,
+					},
+					map[string]attr.Value{
+						"nested_computed": types.StringValue("statevalue1"),
+					},
+				),
+			},
+			expectedResp: ModifyAttributePlanResponse{
+				AttributePlan: types.ObjectValueMust(
+					map[string]attr.Type{
+						"nested_computed": types.StringType,
+					},
+					map[string]attr.Value{
+						"nested_computed": types.StringValue("statevalue1"),
+					},
+				),
+			},
+		},
 		"block-requires-replacement": {
 			block: testschema.BlockWithListPlanModifiers{
 				Attributes: map[string]fwschema.Attribute{