diff --git a/packages/flutter/lib/src/fn3/mimic.dart b/packages/flutter/lib/src/fn3/mimic.dart
index b331366e1d..2933be6cd8 100644
--- a/packages/flutter/lib/src/fn3/mimic.dart
+++ b/packages/flutter/lib/src/fn3/mimic.dart
@@ -52,7 +52,7 @@ class MimicableState extends State<Mimicable> {
   }
 
   void _stopMimic() {
-    assert(!_beingMimicked);
+    assert(_beingMimicked);
     if (!mounted) {
       _beingMimicked = false;
       return;