Just played a game 1 minute ago. It was pugs vs a premade and we were completely rofl-stomped. You need to seriously increase the mmr rating of a group of five if they are a premade. Pugs have no chance at the moment. Or just match premades against premades, that would be fine too.
My three matches before the most recent one were also very one-sided losses but I didn’t check to see if the enemy was a group of five.