diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.new.js b/packages/react-reconciler/src/ReactFiberCommitWork.new.js
index a68e489dccc98..f9d9ad39999f5 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.new.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.new.js
@@ -2131,8 +2131,7 @@ function commitMutationEffectsOnFiber(finishedWork: Fiber, root: FiberRoot) {
         }
         break;
       }
-      case OffscreenComponent:
-      case LegacyHiddenComponent: {
+      case OffscreenComponent: {
         const newState: OffscreenState | null = finishedWork.memoizedState;
         const isHidden = newState !== null;
         const current = finishedWork.alternate;
@@ -2145,27 +2144,26 @@ function commitMutationEffectsOnFiber(finishedWork: Fiber, root: FiberRoot) {
           hideOrUnhideAllChildren(offscreenBoundary, isHidden);
         }
 
-        if (isHidden) {
-          if (!wasHidden) {
-            if (
-              enableSuspenseLayoutEffectSemantics &&
-              (offscreenBoundary.mode & ConcurrentMode) !== NoMode
-            ) {
-              nextEffect = offscreenBoundary;
-              let offscreenChild = offscreenBoundary.child;
-              while (offscreenChild !== null) {
-                nextEffect = offscreenChild;
-                disappearLayoutEffects_begin(offscreenChild);
-                offscreenChild = offscreenChild.sibling;
+        if (enableSuspenseLayoutEffectSemantics) {
+          if (isHidden) {
+            if (!wasHidden) {
+              if ((offscreenBoundary.mode & ConcurrentMode) !== NoMode) {
+                nextEffect = offscreenBoundary;
+                let offscreenChild = offscreenBoundary.child;
+                while (offscreenChild !== null) {
+                  nextEffect = offscreenChild;
+                  disappearLayoutEffects_begin(offscreenChild);
+                  offscreenChild = offscreenChild.sibling;
+                }
               }
             }
+          } else {
+            if (wasHidden) {
+              // TODO: Move re-appear call here for symmetry?
+            }
           }
-        } else {
-          if (wasHidden) {
-            // TODO: Move re-appear call here for symmetry?
-          }
+          break;
         }
-        break;
       }
     }
   }
diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.old.js b/packages/react-reconciler/src/ReactFiberCommitWork.old.js
index aea3e36ed09d2..60c230cd251be 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.old.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.old.js
@@ -2131,8 +2131,7 @@ function commitMutationEffectsOnFiber(finishedWork: Fiber, root: FiberRoot) {
         }
         break;
       }
-      case OffscreenComponent:
-      case LegacyHiddenComponent: {
+      case OffscreenComponent: {
         const newState: OffscreenState | null = finishedWork.memoizedState;
         const isHidden = newState !== null;
         const current = finishedWork.alternate;
@@ -2145,27 +2144,26 @@ function commitMutationEffectsOnFiber(finishedWork: Fiber, root: FiberRoot) {
           hideOrUnhideAllChildren(offscreenBoundary, isHidden);
         }
 
-        if (isHidden) {
-          if (!wasHidden) {
-            if (
-              enableSuspenseLayoutEffectSemantics &&
-              (offscreenBoundary.mode & ConcurrentMode) !== NoMode
-            ) {
-              nextEffect = offscreenBoundary;
-              let offscreenChild = offscreenBoundary.child;
-              while (offscreenChild !== null) {
-                nextEffect = offscreenChild;
-                disappearLayoutEffects_begin(offscreenChild);
-                offscreenChild = offscreenChild.sibling;
+        if (enableSuspenseLayoutEffectSemantics) {
+          if (isHidden) {
+            if (!wasHidden) {
+              if ((offscreenBoundary.mode & ConcurrentMode) !== NoMode) {
+                nextEffect = offscreenBoundary;
+                let offscreenChild = offscreenBoundary.child;
+                while (offscreenChild !== null) {
+                  nextEffect = offscreenChild;
+                  disappearLayoutEffects_begin(offscreenChild);
+                  offscreenChild = offscreenChild.sibling;
+                }
               }
             }
+          } else {
+            if (wasHidden) {
+              // TODO: Move re-appear call here for symmetry?
+            }
           }
-        } else {
-          if (wasHidden) {
-            // TODO: Move re-appear call here for symmetry?
-          }
+          break;
         }
-        break;
       }
     }
   }
diff --git a/packages/react-reconciler/src/ReactFiberCompleteWork.new.js b/packages/react-reconciler/src/ReactFiberCompleteWork.new.js
index 32b9587f26314..b6feee098b4f4 100644
--- a/packages/react-reconciler/src/ReactFiberCompleteWork.new.js
+++ b/packages/react-reconciler/src/ReactFiberCompleteWork.new.js
@@ -1361,7 +1361,9 @@ function completeWork(
         const prevIsHidden = prevState !== null;
         if (
           prevIsHidden !== nextIsHidden &&
-          newProps.mode !== 'unstable-defer-without-hiding'
+          newProps.mode !== 'unstable-defer-without-hiding' &&
+          // LegacyHidden doesn't do any hiding — it only pre-renders.
+          workInProgress.tag !== LegacyHiddenComponent
         ) {
           workInProgress.flags |= Visibility;
         }
diff --git a/packages/react-reconciler/src/ReactFiberCompleteWork.old.js b/packages/react-reconciler/src/ReactFiberCompleteWork.old.js
index 60359fd42d8de..612ad2db52c9f 100644
--- a/packages/react-reconciler/src/ReactFiberCompleteWork.old.js
+++ b/packages/react-reconciler/src/ReactFiberCompleteWork.old.js
@@ -1361,7 +1361,9 @@ function completeWork(
         const prevIsHidden = prevState !== null;
         if (
           prevIsHidden !== nextIsHidden &&
-          newProps.mode !== 'unstable-defer-without-hiding'
+          newProps.mode !== 'unstable-defer-without-hiding' &&
+          // LegacyHidden doesn't do any hiding — it only pre-renders.
+          workInProgress.tag !== LegacyHiddenComponent
         ) {
           workInProgress.flags |= Visibility;
         }
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
index 2915b1e769f04..9f9225fea3bad 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
@@ -337,4 +337,52 @@ describe('ReactOffscreen', () => {
       expect(root).toMatchRenderedOutput(<span prop="Child" />);
     }
   });
+
+  // @gate experimental || www
+  it('does not toggle effects for LegacyHidden component', async () => {
+    // LegacyHidden is meant to be the same as offscreen except it doesn't
+    // do anything to effects. Only used by www, as a temporary migration step.
+    function Child({text}) {
+      useLayoutEffect(() => {
+        Scheduler.unstable_yieldValue('Mount layout');
+        return () => {
+          Scheduler.unstable_yieldValue('Unmount layout');
+        };
+      }, []);
+      return <Text text="Child" />;
+    }
+
+    const root = ReactNoop.createRoot();
+    await act(async () => {
+      root.render(
+        <LegacyHidden mode="visible">
+          <Child />
+        </LegacyHidden>,
+      );
+    });
+    expect(Scheduler).toHaveYielded(['Child', 'Mount layout']);
+
+    await act(async () => {
+      root.render(
+        <LegacyHidden mode="hidden">
+          <Child />
+        </LegacyHidden>,
+      );
+    });
+    expect(Scheduler).toHaveYielded(['Child']);
+
+    await act(async () => {
+      root.render(
+        <LegacyHidden mode="visible">
+          <Child />
+        </LegacyHidden>,
+      );
+    });
+    expect(Scheduler).toHaveYielded(['Child']);
+
+    await act(async () => {
+      root.render(null);
+    });
+    expect(Scheduler).toHaveYielded(['Unmount layout']);
+  });
 });