diff --git a/core/editor.ts b/core/editor.ts
index 3a01bb55ab..209dedaf3c 100644
--- a/core/editor.ts
+++ b/core/editor.ts
@@ -6,6 +6,7 @@ import Delta, { AttributeMap, Op } from 'quill-delta';
 import Block, { BlockEmbed, bubbleFormats } from '../blots/block';
 import Break from '../blots/break';
 import CursorBlot from '../blots/cursor';
+import Embed from '../blots/embed';
 import Scroll from '../blots/scroll';
 import TextBlot, { escapeText } from '../blots/text';
 import { Range } from './selection';
@@ -30,17 +31,17 @@ class Editor {
     normalizedDelta.reduce((index, op) => {
       const length = Op.length(op);
       let attributes = op.attributes || {};
-      let addedNewline = false;
+      let isImplicitNewlinePrepended = false;
+      let isImplicitNewlineAppended = false;
       if (op.insert != null) {
         deleteDelta.retain(length);
         if (typeof op.insert === 'string') {
           const text = op.insert;
-          // @ts-expect-error TODO: Fix this the next time the file is edited.
-          addedNewline =
+          isImplicitNewlineAppended =
             !text.endsWith('\n') &&
             (scrollLength <= index ||
               // @ts-expect-error
-              this.scroll.descendant(BlockEmbed, index)[0]);
+              !!this.scroll.descendant(BlockEmbed, index)[0]);
           this.scroll.insertAt(index, text);
           const [line, offset] = this.scroll.line(index);
           let formats = merge({}, bubbleFormats(line));
@@ -53,12 +54,30 @@ class Editor {
         } else if (typeof op.insert === 'object') {
           const key = Object.keys(op.insert)[0]; // There should only be one key
           if (key == null) return index;
-          // @ts-expect-error TODO: Fix this the next time the file is edited.
-          addedNewline =
-            this.scroll.query(key, Scope.INLINE) != null &&
-            (scrollLength <= index ||
+          const isInlineEmbed = this.scroll.query(key, Scope.INLINE) != null;
+          if (isInlineEmbed) {
+            if (
+              scrollLength <= index ||
               // @ts-expect-error
-              this.scroll.descendant(BlockEmbed, index)[0]);
+              !!this.scroll.descendant(BlockEmbed, index)[0]
+            ) {
+              isImplicitNewlineAppended = true;
+            }
+          } else if (index > 0) {
+            // @ts-expect-error
+            const [leaf, offset] = this.scroll.descendant(LeafBlot, index - 1);
+            if (leaf instanceof TextBlot) {
+              const text = leaf.value();
+              if (text[offset] !== '\n') {
+                isImplicitNewlinePrepended = true;
+              }
+            } else if (
+              leaf instanceof Embed &&
+              leaf.statics.scope === Scope.INLINE_BLOT
+            ) {
+              isImplicitNewlinePrepended = true;
+            }
+          }
           this.scroll.insertAt(index, key, op.insert[key]);
         }
         scrollLength += length;
@@ -74,10 +93,13 @@ class Editor {
       Object.keys(attributes).forEach(name => {
         this.scroll.formatAt(index, length, name, attributes[name]);
       });
-      const addedLength = addedNewline ? 1 : 0;
-      scrollLength += addedLength;
+      const prependedLength = isImplicitNewlinePrepended ? 1 : 0;
+      const addedLength = isImplicitNewlineAppended ? 1 : 0;
+      scrollLength += addedLength + prependedLength;
+      console.log(JSON.stringify(deleteDelta.ops));
       deleteDelta.delete(addedLength);
-      return index + length + addedLength;
+      deleteDelta.retain(prependedLength);
+      return index + length + addedLength + prependedLength;
     }, 0);
     deleteDelta.reduce((index, op) => {
       if (typeof op.delete === 'number') {
diff --git a/test/unit/core/editor.js b/test/unit/core/editor.js
index 9c23be16b1..84cb839ac0 100644
--- a/test/unit/core/editor.js
+++ b/test/unit/core/editor.js
@@ -611,6 +611,32 @@ describe('Editor', function() {
       );
     });
 
+    it('insert block embed to the middle of text and delete', function() {
+      const editor = this.initialize(Editor, `<p><br></p><p>abc</p>`);
+      editor.applyDelta(
+        new Delta()
+          .retain(2)
+          .insert({ video: '#' })
+          .delete(2),
+      );
+      expect(this.container).toEqualHTML(
+        '<p><br></p><p>a</p><iframe class="ql-video" frameborder="0" allowfullscreen="true" src="#"></iframe><p><br></p>',
+      );
+    });
+
+    fit('insert block embed to the end of a line and delete', function() {
+      const editor = this.initialize(Editor, `<p><br></p><p>abc</p><p>def</p>`);
+      editor.applyDelta(
+        new Delta()
+          .retain(5)
+          .insert({ video: '#' })
+          .delete(2),
+      );
+      expect(this.container).toEqualHTML(
+        '<p><br></p><p>abc</p><iframe class="ql-video" frameborder="0" allowfullscreen="true" src="#"></iframe><p>f</p>',
+      );
+    });
+
     it('append formatted block embed', function() {
       const editor = this.initialize(Editor, '<p>0123</p><p><br></p>');
       editor.applyDelta(