To replicate: Play Teams deathmatch or Squad TD (though I'm pretty sure it happens in other modes too). When you die, instead of pressing space bar to respawn, press y to change classes, change to a new class. Then, your screen will not move on. You can't be revived, you can't die, you can't go to the respawn screen, you're in purgatory until the game kicks you out for inactivity or you voluntarily leave the match.
So far this has happened to me at least 2-3 times per game session/day. When playing these modes I often wait for a respawn to save points, but while I'm waiting, I'm switching to a new class to try and be quick then I get in this limbo. This has been happening for at least a week or two.
happens in domination too
