After the new commenting system, we get messages like this:

Where it looks like @Untitled Contact is replying to himself. But the UI makes him think that he is participating in a thread. So now if I'm using the protocol and trying to understand what happened, I can't see who he is replying to.

I think this is a pretty severe issue, because the conversation is now nonsensical from the protocol perspective. If a message does not target the correct context, then we can no longer promise semantic robustness of their communications.