I've got a rating of around 800-900 with just over 2000 games, played over a period of around 10 years. I play mostly 3v3 / 4v4
I've started noticing that when I WIN a game teamed up with players who have fewer games (Still non-grey) and a higher rating than me their rating increases MORE than mine does.
Similarly if I lose a game teamed up with players with a higher rating than me then my rating decreases more than theirs does.
These two together seem to not make sense to me. I get that a high number of games would in theory mean my rating is more accurate and therefore shouldn't be influenced as much by a single game, but then by the same token my rating shouldn't decrease as much when I lose, especially when my team were ranked more highly than me.
It's almost as though number of games is being taken into account as a sort of hidden addition to the rating.
The trouble is imagine I always play completely balanced games and win 50% my rating is going to go down over time.
I don't know whether this is relevant but about 1/3 of my games are played with the same two friends who are probably worse than me but have higher ratings, and unlike me they never play with anyone else.
I can share examples if anyone is actually interested.