I notice that every now and then; often shortly after I log in, the game’s FPS goes way down to around 40 or 60, and stays there until I switch graphical settings. It doesn’t matter which setting I switch to, or whether I switch back to the original graphical settings, but switching graphics settings will fix the issue until it seemingly randomly happens again.
Yeah that is a known Unity bug, just keep your window focused and it won’t happen, we are working on integrating a fix they did but it requires us to update Unity versions so we haven’t done it yet.