I've been having the same problem since update 34 dropped and it's gotten much, much worse with update 35 (it happens about 2 out of every 3 random matchmaking missions for me). And it happens *every* time I zone into Sanctum Anatomica, which means getting bounced from one of the new missions means I also have to sit through 20-30 seconds of a frozen screen as a reward for the matchmaking fail. Whee.
Playing on a PS5, usual disclaimers about a hardwired cat 5e connection to my router, real non-tin can and string internet connection, blah, blah, blah. Never saw any problems like this before Dagath.