MM versus win streaks
Situation happens pretty frequently because the matchmaker is trying to find you a game. More often than not, you either get paired with those under your rating or above…or go against them instead. Might be because the system is trying to give you an outlier match to either boost your rating up a bit more or take you down..or just because there are no players available and you’ve been in queue for so long. This happens more frequently as you play off-hours and start seeing Duos more often.
Sometimes it better to lose maybe 4 rating against Duos of +300 rating above you rather than losing -20 with them. At the same time, there is a possibility of beating those +300 above you and getting +20.
It definitely is somewhat predictable though, especially Solo.