I use Lightroom Cloud v 9.4.1. Since the most recent updates, subtraction to the mask with a brush isn't working.

I use Lightroom Cloud v 9.4.1. Since the most recent updates, when I create a mask and then try to subtract an area from it, I can't see any of what I'm brushing disappear (meaning the pink overlay is not getting erased). If I go to a large pink area and try to brush it, I see a very light removal, but it's clearly not removing the area desired. I have density all the way to the right. Any ideas if this is a preference that got changed or if this is a bug? Thanks to anyone who can help.