question: No notification when the other user replies to their own thread in 1:1 DMs. Expected or unexpected behavior?

[maximetinu]

Description
In a 1:1 DM channel, if User A starts a thread on their own message and replies, User B doesn't receive any notification unless they are explicitly mentioned.

This feels unexpected for 1:1 DMs. In similar apps (Slack), any thread activity in a direct message notifies both parties because the context implies a private conversation where both people are subscribed. Currently, Stream Chat seems to treat 1:1 DMs like group channels, requiring explicit participation to get notified.

To Reproduce

1. User A and User B have a 1:1 DM channel (messaging type, 2 members).
2. User A sends a message: "Hey check this out".
3. User B reads and closes the chat.
4. User A clicks "Reply in thread" on their own message and sends: "Here's more context".
5. User B checks their Threads view → No notification, no unread badge, and the thread doesn't appear.

Expected behavior
User B should automatically receive notification.thread_message_new events for any thread activity in a 1:1 DM, even without a mention.

Current workaround
We are currently patching this by auto-injecting the other DM member into mentioned_users for thread replies via doSendMessageRequest.

// Simplified example
if (isThreadReply && is1on1DM) {
  message.mentioned_users = [...existingMentions, otherMemberId];
}

This works (events deliver, unread count updates, and queryThreads works), but it feels like a workaround that shouldn't be necessary for direct messages.

Questions

1. Is this intentional behavior? It makes sense for group channels to avoid spam, but feels wrong for 1:1s.
2. Is there some configuration that I'm missing to auto-notify both members in 2-person channels?

Package version

• stream-chat: 8.48.0
• stream-chat-react: 12.x (forked)