I'm asking this question again since my first post did not get any answers anymore and my question is still open:
I'm using the current basic steam version of blender and want to use vertex paint with the paint mask feature, so the color stops at the edge of each face and does not " bleed " over to the next faces.
It suddenly stopped working since Blender 3.5 I made a little video directly showing the problem:
Can you please help me somehow get it working again? Essentially this: