diff --git a/packages/stream_chat/CHANGELOG.md b/packages/stream_chat/CHANGELOG.md
index 82225b27..ef66f835 100644
--- a/packages/stream_chat/CHANGELOG.md
+++ b/packages/stream_chat/CHANGELOG.md
@@ -10,6 +10,7 @@
 - [[#890]](https://github.com/GetStream/stream-chat-flutter/pull/890) Fixed Reactions not updating on thread messages.
   Thanks [bstolinski](https://github.com/bstolinski).
 - [[#897]](https://github.com/GetStream/stream-chat-flutter/issues/897) Fixed error type mis-match in `AuthInterceptor`.
+- Fix `channelState.copyWith` with respect to pinnedMessages.
 
 ## 3.4.0
 
diff --git a/packages/stream_chat/lib/src/client/channel.dart b/packages/stream_chat/lib/src/client/channel.dart
index 76fbab7a..dd6fcff1 100644
--- a/packages/stream_chat/lib/src/client/channel.dart
+++ b/packages/stream_chat/lib/src/client/channel.dart
@@ -1744,15 +1744,6 @@ class ChannelClientState {
         ownReactions: oldMessage?.ownReactions,
       );
       addMessage(message);
-
-      if (message.pinned) {
-        _channelState = _channelState.copyWith(
-          pinnedMessages: [
-            ..._channelState.pinnedMessages,
-            message,
-          ],
-        );
-      }
     }));
   }
 
@@ -1804,8 +1795,24 @@ class ChannelClientState {
         newMessages.add(message);
       }
 
+      final newPinnedMessages = [...pinnedMessages];
+      final oldPinnedIndex =
+          newPinnedMessages.indexWhere((m) => m.id == message.id);
+
+      // Handle pinned messages
+      if (message.pinned) {
+        if (oldPinnedIndex != -1) {
+          newPinnedMessages[oldPinnedIndex] = message;
+        } else {
+          newPinnedMessages.add(message);
+        }
+      } else {
+        newPinnedMessages.removeWhere((m) => m.id == message.id);
+      }
+
       _channelState = _channelState.copyWith(
         messages: newMessages..sort(_sortByCreatedAt),
+        pinnedMessages: newPinnedMessages,
         channel: _channelState.channel?.copyWith(
           lastMessageAt: message.createdAt,
         ),
@@ -1898,11 +1905,12 @@ class ChannelClientState {
       .distinct(const ListEquality().equals);
 
   /// Channel pinned message list.
-  List<Message> get pinnedMessages => _channelState.pinnedMessages.toList();
+  List<Message> get pinnedMessages => _channelState.pinnedMessages;
 
   /// Channel pinned message list as a stream.
-  Stream<List<Message>> get pinnedMessagesStream =>
-      channelStateStream.map((cs) => cs.pinnedMessages.toList());
+  Stream<List<Message>> get pinnedMessagesStream => channelStateStream
+      .map((cs) => cs.pinnedMessages)
+      .distinct(const ListEquality().equals);
 
   /// Get channel last message.
   Message? get lastMessage =>
@@ -2213,7 +2221,7 @@ class ChannelClientState {
             .toList();
 
         updateChannelState(_channelState.copyWith(
-          pinnedMessages: pinnedMessages.where(_pinIsValid()).toList(),
+          pinnedMessages: pinnedMessages.where(_pinIsValid).toList(),
           messages: expiredMessages,
         ));
       }
@@ -2250,7 +2258,7 @@ class ChannelClientState {
   }
 }
 
-bool Function(Message) _pinIsValid() {
+bool _pinIsValid(Message message) {
   final now = DateTime.now();
-  return (Message m) => m.pinExpires!.isAfter(now);
+  return message.pinExpires!.isAfter(now);
 }
diff --git a/packages/stream_chat/lib/src/core/models/channel_state.dart b/packages/stream_chat/lib/src/core/models/channel_state.dart
index 3ddc2b68..17439dc0 100644
--- a/packages/stream_chat/lib/src/core/models/channel_state.dart
+++ b/packages/stream_chat/lib/src/core/models/channel_state.dart
@@ -56,7 +56,7 @@ class ChannelState {
     ChannelModel? channel,
     List<Message>? messages,
     List<Member>? members,
-    List<Message>? pinnedMessages,
+    List<Message> pinnedMessages = _emptyPinnedMessages,
     int? watcherCount,
     List<User>? watchers,
     List<Read>? read,
@@ -69,7 +69,7 @@ class ChannelState {
         // FIXME: Use non-nullable by default instead of empty list.
         pinnedMessages: pinnedMessages == _emptyPinnedMessages
             ? this.pinnedMessages
-            : pinnedMessages ?? _emptyPinnedMessages,
+            : pinnedMessages,
         watcherCount: watcherCount ?? this.watcherCount,
         watchers: watchers ?? this.watchers,
         read: read ?? this.read,