MMR increase/decrease issues (NOT LEAGUE PLACEMENT RELATED)

I have given up on the league placement bug, as i understand it has been an issue for a few years now.

But my problem now is that I sometimes play with higher MMR players, and when i lose, i lose 20+ points, whilst they gain 70-100 MMR. I don’t understand how this works. I have at least 4 images i captured as evidence, but i don’t know what the best way is to upload them.

Most likely it was a placement match for them, you gain waaay more in those if you win