Maybe someone has an idea I didn't try yet.
So this doesn't happen at every time of day, but more often than not: While my mask cam view on the iPhone software seems to do perfectly fine, my model within Vtube studio is just opening their mouth despite my actual mouth being completely shut. Checking within Vtube Studio, my "closed" value seems to randomly rise up to 0.2ish, when moving my face around (or when simply looking at the camera dead pan).
I do not know why this happens, and why it doesn't always happen. Might be lighting, but I do have a pretty substantial LED keylight over my screen. Might be the camera distance, but usually my phone rests comfortably on a phone stand an arm length away, directly in front of my mug. Might be the beard (?), which is a theory underlined by my mouth also opening a lot when i do, like, "kissing" movements with it in lack of a better term.
I only bought this phone back then because I was annoyed with the webcam not working great with my glasses, but while the phone also doesn't like them, this is now an additional issue. I noticed this in the evening more than over the day, so "lighting" is my best bet, but I have no idea how to fix it.
If anyone has any clue or managed to fix the same issue, I'm happy for any input. Thanks!