Google translate:
I noticed a problem with the brush tool when I use it to mask a layer, the tool does not apply the brush to the region I select, as if it were a "miss click". I recorded a video for reference:
Reply:
It looks like you have a very large scatter setting on your Brush. Open your Brush Settings panel and see if "Scattering" is checked. You can uncheck it or select different settings. Or you can select a different Brush preset that doesn't use scattering