Riot's matchmaking back at it again?

So my friend was playing a game in promos at b4, her solo mmr is b2. Personally i think they have improved a lotm but by no means do i think they couldve ever won that last game. She was playing eve. Look her up at LNast. Khazix was silver 5. I am not going to even bring up the fact that khazix is super broken right now. Anyways, she lost, obviously. She is b4 regardless. Regardless of mmr, her rank, is b4. She should play against her rank. Not against some person who purposefully forces their mmr to lower so they can get easier wins, or someone higher than her in general. I swear it's like whoever created the format of matchmaking had a stroke and people just forgot about it