Originally Posted by
Eukamel
Your teams mmr that you see after each game is calculated by the average mmr of your team members. So let's say you play 3v3 with two friends and get a team up to 1500 rating with a matching mmr. If you then were to leave the team and join another team with 2 members whose individual mmr might be 1800 and 1900 the mmr you'd see after each game would all of a sudden be 1733. And because of that you'd see a huge increase in mmr. So basically if you have a team at low rating (members with low mmr) and then join a team with high rating (members with high mmr) the teams average mmr (the one displayed after each game) will be higher than your old one. So basically what happens is just your average mmr (the teams mmr) getting higher because of your new team mates having a higher mmr than your old ones. Your personal mmr hasn't been changed though. If you were to join a team with lower rating than your old one (members with low mmr) you'd see the exact opposite of what you're experiensing, a lower team mmr. All in all it's working as intended.