Photohop 2021 Masking issues
Since the newest photoshop version, masking isn't working properly anymore.
When I use the brush or filling tool with 100% black, the part of the layer i wanted to mask out is still slightly visible.



When I switch to the channels and use the brush again, it's finally at 100% and therefore invisible.


But switching back to the layers and painting again with 100% black, it reappears...

I've checked everything, the creative cloud is up to date, so is the iMac - since today I'm working with macOs Big Sur - still the same issues. Right now I have to work with the old 2020 version to avoid this problem.
Anybody got an idea?
Thanks for your help.