Different msq quest same issue.
The Jewel of Thavnair
9pm Eorzean Time
8:00 pm EST

This is the cutscene with Vrtra.

This also is happening on a close up with Yshtola and all the other Scions after asking a question and receiving a response.

You can visibly see lines in her hair and character model being rendered in the lighting.

This affects all scions within this cutscene.

Ok I've narrowed down based on watching the cutscenes in question that it has to do with movement within the cutscenes.