Lip sync looks cartoonish, teeth way too visible, how do I fix this?

Hey everyone, been playing around with Veo 3.1 and I keep running into the same issue no matter how I phrase my prompts.

Whenever I generate a character speaking or rapping, the lip sync looks completely unnatural, the mouth opens way too wide, the upper teeth are always super visible like a cartoon character talking, and the whole jaw movement feels exaggerated and stiff. It doesn't look like a real person speaking at all.

I've already tried specifying things like "natural lip movement", "mouth barely open", "relaxed jaw", "teeth not visible", "subtle articulation" directly in the prompt but nothing seems to make a significant difference. The model just does its own thing with the mouth.

Has anyone found a reliable way to control this? Is there a specific phrasing or trick that actually works? Or is this just a current limitation of the model that we have to live with for now?

Any help appreciated 🙏