What was the highest 3v3 rating ever in any part of the world?

It was fixed before the season ended, but that didn’t stop a lot of people from obtaining achievements they otherwise would’ve been unable to, and led to the top players going even higher.

They had also changed it for the removal of battlegroups together with the launch of S14.

It’s just the “inner workings” of their system, which isn’t announced in change logs. It’s easily inferred as long as you understand the fundamental principles of rating systems on a mechanical level though.