This just... happens. I'm not sure the cause of it, but I think its from FPS irregularities in PNGTuber Plus from your PC divying up resources between the app and the game you're running. Less graphically resource intensive games tends to have less chance of making the model explode and going - as my chat likes to call it - biblically accurate.
The dev has implied that he might have a fix over twitter, I think, so maybe we'll see a fix soon!