During this morning's maintenance we updated the matchmaking server rules. You will no longer be matched against the same player repeatedly.
We were also seeing players get stuck in the ranked matchmaking queue, requiring leaving and re-entering the queue. We're still tracking down all the cases of this but it should be better. If you are getting stuck (in queue for 4+ minutes) please post or PM me your name, platform (Steam or GOG), and the approximate time.