diff --git a/src/fragments/lib/datastore/flutter/data-access/update-snippet.mdx b/src/fragments/lib/datastore/flutter/data-access/update-snippet.mdx
index bebac670813..e989e7db905 100644
--- a/src/fragments/lib/datastore/flutter/data-access/update-snippet.mdx
+++ b/src/fragments/lib/datastore/flutter/data-access/update-snippet.mdx
@@ -19,3 +19,15 @@ Future<void> updatePost() async {
   }
 }
 ```
+
+<Callout>
+
+`copyWith` cannot assign `null` to a nullable field: a null argument keeps the current value. Use `copyWithModelFieldValues` instead:
+
+</Callout>
+
+```dart
+final newPost = oldPost.copyWithModelFieldValues(
+  content: ModelFieldValue.value(null),
+);
+```
diff --git a/src/fragments/lib/graphqlapi/flutter/mutate-data.mdx b/src/fragments/lib/graphqlapi/flutter/mutate-data.mdx
index 3472dce68f8..a6de33eefc0 100644
--- a/src/fragments/lib/graphqlapi/flutter/mutate-data.mdx
+++ b/src/fragments/lib/graphqlapi/flutter/mutate-data.mdx
@@ -18,6 +18,24 @@ Future<void> updateTodo(Todo originalTodo) async {
 }
 ```
 
+<Callout>
+
+`copyWith` cannot assign `null` to a nullable field: a null argument keeps the current value. Use `copyWithModelFieldValues` instead:
+
+</Callout>
+
+```dart
+Future<void> clearTodoDescription(Todo originalTodo) async {
+  final cleared = originalTodo.copyWithModelFieldValues(
+    description: ModelFieldValue.value(null),
+  );
+
+  final request = ModelMutations.update(cleared);
+  final response = await Amplify.API.mutate(request: request).response;
+  safePrint('Response: $response');
+}
+```
+
 To delete the `Todo`:
 
 ```dart
diff --git a/src/pages/[platform]/build-a-backend/data/data-modeling/relationships/index.mdx b/src/pages/[platform]/build-a-backend/data/data-modeling/relationships/index.mdx
index f36b8f92d7d..bb380a78187 100644
--- a/src/pages/[platform]/build-a-backend/data/data-modeling/relationships/index.mdx
+++ b/src/pages/[platform]/build-a-backend/data/data-modeling/relationships/index.mdx
@@ -263,7 +263,9 @@ do {
 <InlineFilter filters={["flutter"]}>
 
 ```dart
-final memberWithRemovedTeam = existingMember.copyWith(team: null);
+final memberWithRemovedTeam = existingMember.copyWithModelFieldValues(
+  teamId: ModelFieldValue.value(null),
+);
 final memberRemoveRequest = ModelMutations.update(memberWithRemovedTeam);
 final memberRemoveResponse = await Amplify.API.mutate(request: memberRemoveRequest).response;
 ```
@@ -687,7 +689,9 @@ do {
 <InlineFilter filters={["flutter"]}>
 
 ```dart
-final cartWithRemovedCustomer = existingCart.copyWith(customer: null);
+final cartWithRemovedCustomer = existingCart.copyWithModelFieldValues(
+  customerId: ModelFieldValue.value(null),
+);
 final cartRemoveRequest = ModelMutations.update(cartWithRemovedCustomer);
 final cartRemoveResponse = await Amplify.API.mutate(request: cartRemoveRequest).response;
 ```
diff --git a/src/pages/[platform]/build-a-backend/data/mutate-data/index.mdx b/src/pages/[platform]/build-a-backend/data/mutate-data/index.mdx
index 53ca2a1fc8d..0da3662f09c 100644
--- a/src/pages/[platform]/build-a-backend/data/mutate-data/index.mdx
+++ b/src/pages/[platform]/build-a-backend/data/mutate-data/index.mdx
@@ -293,6 +293,24 @@ Future<void> updateTodo(Todo originalTodo) async {
 }
 ```
 
+<Callout>
+
+`copyWith` cannot assign `null` to a nullable field: a null argument keeps the current value. Use `copyWithModelFieldValues` instead:
+
+</Callout>
+
+```dart
+Future<void> clearTodoDescription(Todo originalTodo) async {
+  final cleared = originalTodo.copyWithModelFieldValues(
+    description: ModelFieldValue.value(null),
+  );
+
+  final request = ModelMutations.update(cleared);
+  final response = await Amplify.API.mutate(request: request).response;
+  safePrint('Response: $response');
+}
+```
+
 </InlineFilter>
 
 ## Delete an item
diff --git a/src/pages/[platform]/frontend/data/mutate-data/index.mdx b/src/pages/[platform]/frontend/data/mutate-data/index.mdx
index dc201477329..67b72d189ad 100644
--- a/src/pages/[platform]/frontend/data/mutate-data/index.mdx
+++ b/src/pages/[platform]/frontend/data/mutate-data/index.mdx
@@ -293,6 +293,24 @@ Future<void> updateTodo(Todo originalTodo) async {
 }
 ```
 
+<Callout>
+
+`copyWith` cannot assign `null` to a nullable field: a null argument keeps the current value. Use `copyWithModelFieldValues` instead:
+
+</Callout>
+
+```dart
+Future<void> clearTodoDescription(Todo originalTodo) async {
+  final cleared = originalTodo.copyWithModelFieldValues(
+    description: ModelFieldValue.value(null),
+  );
+
+  final request = ModelMutations.update(cleared);
+  final response = await Amplify.API.mutate(request: request).response;
+  safePrint('Response: $response');
+}
+```
+
 </InlineFilter>
 
 ## Delete an item