Brush tool leaves trail of black boxes when painting on layer mask

In PS 2020 when using the brush or pencil tool of any kind, it will leave a trail of black boxes as I paint or draw on a layer mask or the mask alpha channel. The image returns to normal when I toggle layer visiblilty, but this makes it impossible to use masks properly.

Edit: I have noticed that this occurs with the most frequency when I'm using a clipping path linked to something being masked, but it's not restricted to that, it's just far more common an issue in those cases.

I have a Nivida GeForce 1060 6GB

INtel Core i7-8700 @ 3.2ghz

64GB of RAM

All drivers are up to date.

Attached are visuals of the issue I'm referring to.

Any insight into how this happened will be much appreciated.