why hands or mics over the mouth completely break most AI lipsync tools (and how to fix it)

After testing a bunch of lipsync tools, there’s one failure mode I can’t unsee anymore. The moment something crosses the mouth, hand, mic, whatever, most tools still just… fall apart You still get: 1/ a mouth painted on top of a hand 2/ teeth on a micro/ flickering lips fighting the occluder It looks straight up cursed. So I dug in deeper. What’s happening (from what I can tell) is most models aren’t reasoning about visibility, they’re just trying to generate a mouth every frame, so even if the mouth is blocked, they still try to “draw” it.