diff --git a/x-pack/plugins/fleet/common/types/models/agent.ts b/x-pack/plugins/fleet/common/types/models/agent.ts
index e561613934a04..e52edb821b1d7 100644
--- a/x-pack/plugins/fleet/common/types/models/agent.ts
+++ b/x-pack/plugins/fleet/common/types/models/agent.ts
@@ -95,10 +95,13 @@ export interface Agent extends AgentBase {
   access_api_key?: string;
   // @deprecated
   default_api_key_history?: FleetServerAgent['default_api_key_history'];
-  outputs?: Array<{
-    api_key_id: string;
-    to_retire_api_key_ids?: FleetServerAgent['default_api_key_history'];
-  }>;
+  outputs?: Record<
+    string,
+    {
+      api_key_id: string;
+      to_retire_api_key_ids?: FleetServerAgent['default_api_key_history'];
+    }
+  >;
   status?: AgentStatus;
   packages: string[];
   sort?: Array<number | string | null>;
diff --git a/x-pack/plugins/fleet/server/services/agents/unenroll.test.ts b/x-pack/plugins/fleet/server/services/agents/unenroll.test.ts
index 9169df19fbcfb..b1e69fa861488 100644
--- a/x-pack/plugins/fleet/server/services/agents/unenroll.test.ts
+++ b/x-pack/plugins/fleet/server/services/agents/unenroll.test.ts
@@ -331,15 +331,22 @@ describe('invalidateAPIKeysForAgents', () => {
             id: 'defaultApiKeyHistory2',
           },
         ],
-        outputs: [
-          {
+        outputs: {
+          output1: {
             api_key_id: 'outputApiKey1',
             to_retire_api_key_ids: [{ id: 'outputApiKeyRetire1' }, { id: 'outputApiKeyRetire2' }],
           },
-          {
+          output2: {
             api_key_id: 'outputApiKey2',
           },
-        ],
+          output3: {
+            api_key_id: 'outputApiKey3',
+            to_retire_api_key_ids: [
+              // Somes Fleet Server agents don't have an id here (probably a bug)
+              { retired_at: 'foo' },
+            ],
+          },
+        },
       } as any,
     ]);
 
@@ -353,6 +360,7 @@ describe('invalidateAPIKeysForAgents', () => {
       'outputApiKeyRetire1',
       'outputApiKeyRetire2',
       'outputApiKey2',
+      'outputApiKey3',
     ]);
   });
 });
diff --git a/x-pack/plugins/fleet/server/services/agents/unenroll_action_runner.ts b/x-pack/plugins/fleet/server/services/agents/unenroll_action_runner.ts
index fed5d44fe98e8..1b17e688a8a26 100644
--- a/x-pack/plugins/fleet/server/services/agents/unenroll_action_runner.ts
+++ b/x-pack/plugins/fleet/server/services/agents/unenroll_action_runner.ts
@@ -216,12 +216,16 @@ export async function invalidateAPIKeysForAgents(agents: Agent[]) {
       agent.default_api_key_history.forEach((apiKey) => keys.push(apiKey.id));
     }
     if (agent.outputs) {
-      agent.outputs.forEach((output) => {
+      Object.values(agent.outputs).forEach((output) => {
         if (output.api_key_id) {
           keys.push(output.api_key_id);
         }
         if (output.to_retire_api_key_ids) {
-          output.to_retire_api_key_ids.forEach((apiKey) => keys.push(apiKey.id));
+          Object.values(output.to_retire_api_key_ids).forEach((apiKey) => {
+            if (apiKey?.id) {
+              keys.push(apiKey.id);
+            }
+          });
         }
       });
     }