Blocked from talking in lobby.

I'm curious as to why I sometimes get blocked from talking in the lobby. This most commonly happens when I join a team builder and am sometimes blocked from talking in the team builder lobby. This usually goes away after a little bit, but I'm curious as to why it even happens in the first place or if this is even a bug. Before you say anything, I am NOT chat restricted, I have NEVER been banned, and I've not even received a warning (except LeaveBuster).

PS: And no I'm not the one spamming in the chat, that is someone else. I literally have not said a single word. (I said gg in game). I would not have censored my name.