The same problem started to happen to me after the latest patch. I can only play 1v1s without it dropping me within the 1st 2-3mins of the game and i never had this problem before the latest patch. My teammate i play with has it happen to him randomly in any size game just not all the time and for him it's been going on like that for the past couple weeks.
I've tried playing around with stuff and no luck (even though i shouldn't have to & my other RTS games i play multi work just fine), so right now i'm stuck to playing 1v1s only. Look at my game stats all those 3v3s dropped trying different stuff and hoping it'd work, but nope just 1v1s.
The multi connection for this game is still FUBAR after all this time 