I feel like this used to work properly until a month or so ago.
The worst bug I've seen, and this is also something that only started happening in the last several months, is select messages simply not appearing! So basically I open my computer in the morning and look at Teams and it'll have messages from overnight. EXCEPT some messages did not make it, like, at all. There was a whole thread that had replies that were simply not visible to me. I even replied to that thread and on my screen the reply appeared right after the last visible message whereas for everyone else it appeared after the 40 or so messages that came in overnight.
I haven't been the only one to run into that issue either. Restarting Teams is the only thing that brought the messages back.
Now that's what I call a critical bug! Who knows how many things I've missed.