Welcome to TVPaint Community forums !

Hello TVP forum!
I'm sadly writing my first post asking for some help. Hopefully next time I can be the one helping out.

That being said, on to business!
This problem is not a problem with my layer style or a problem with my brush settings (I don't think so anyways). This happened with one of my files and now another. I have no clue what is going on. Here are my settings.

I have Mac OS Yosemite
32 bit
TVP 10.0.18 Pro

Any ideas why?

hello and welcome : you have a stencil activated on the "GEM" layer. That's probably the issue.
btw, I think you should update your software to the 10.5.7 version to avoid bugs. It's free in your situation.

thank you! I will look into the update!