I had to change my recording software, literally because of this. My guess is that if you alt-tab, plays.tv stop recording. I missed some high kill games i would have liked to have recorded :( The solution might be to put the game in borderless window instead of fullscreen, but i absolutely don't want any form of input lag.
Please look into it.
Looks like I'm talking to you in the reddit thread right now about this problem as well. I recommended sending in logs since we shouldn't be stopping the recording, only pausing it.