Chris, Thanks for the reply. I can confirm yes to both. If I draw on a mask layer in the same document, I don't have any issues. I can also get it to work in a new document with the same one open. It is very strange.
I have a photo I am trying to process. I wanted to create a new layer and fill it with grey. I created the layer and to my surprise after selecting a color, any color, I can't get it to fill. I then tried to just brush in the color and can't get that to work either. I can see drawings work in another document and if I draw on the mask on it seems to work fine. It is likely user error as I try to make the switch over from PS.