If you reply on someone’s message you see his avatar right above your message. But if you reply on someone’s message and mention someone’s username (exactly during creation of message, not editing), for example, @Rustam then you don’t see the avatar so it’s not clear to which message is your reply addressed.
When you reply to the OP (with a tag and reply) or if you are the OP (and only tag), then you never get a user profile in the top right. It is like a general post.
When you reply to a message below the OP, you do get the user profile in the top right and also that I tagged someone. I am replying to my own post in the example above, but I also want to tag another user that may not be here. The tagged person is not a reply but letting them know you mentioned them in this topic, it is a bit like a CC.
Hmm, ok, thanks for further investigation
Interesting that right now I don’t even tag someone but just reply to your message and don’t see a user profile in the top right.
Hmm, different behavior for two messages as you can see above @ibby though both are replies to your message by me as OP even without a tag.
I think the difference is the location of reply you click? If you click reply to the bottom right of the post you are replying to, it is different than the reply at the bottom of the post.
Okay I will test this one out in the testforum later, I think there might be something off with the rules.