1.No, the bug only occurs after the opponent watched replay, no other message bugs. I noticed this bug few months ago actually ( I didn't report it because it doesnt occur too often, it only occurs when there are longer rally replays ) and I thought its somehow because of my TE but then my friend told me he experienced the same thing. And our menus have never been modded. I think its a matter of seconds, I noticed that the message sticks on the screen when the opponent just watched a rally replay that lasts over 15-20 seconds or more. Usualy after the opponent watched a replay that lasts less than 10 seconds the replay message would dissapear. So any replay that lasts longer than 15 seconds could cause this bug,thats why I said rally replays because they last longer.
2.Btw, these desynchs during matches are killing me. I mean there are points that I won and they got desynched and then we had to replay the point and then I lost the point. This is the most annoying bug at the moment.. I get like 6-7 desynches per match and they occured in EVERY single match that I played since the last build release( I don't understand why, MS is pretty good around 20/30/40 ) so please disable it...

everyone is sick of it