match making is rough..... lots of posts about it and we guess to the reasons because the info is not "official"
but....
if a new acct lv10 for instance has a total of 6 games played, 4 of them they won, then they r sitting on a nice win rate.... maybe something similar to a dia who has thousands of games played.....
a dia wants to play with a friend who is just starting, so they duo, dia mmr is high, the new player mmr is low so the match making trys to equalize it against the other team.... enter 3 plats a bronze and an unranked....
so ya.... can lead to weird games, do a search on the boards, you will see some interesting prntscrns from people having posted some.... in fact let me check if i kept one...brb....
eh, i dont think i kept any of em... but ya do a quick search on the boards under match making and you will find a bunch of good funny ones