Brush and layer mask

[veronicag34860390]

Hi!
So I have a problem with brushing out areas in layer mask after the last Photoshop CC update (21.2.2). When I brush on a layer mask using a regular soft brush (or any other brush) it masks out "boubles", I don't know how else to explain it (see photo). Have any of you seen something like this before and know how to fix it? 
I can't really edit my clients photos with the brush as it is know. 

I'm not using any drawing tools, just the mousepad on my macbook pro. 

[Joely]

Please show us the brush properties…