Colors going crazy randomly?

[Or_David_Shachar]

Hey,

I've been using these basic PS tools for ages, but suddenly this annoying glitch keeps happening:

I'm not using any adjustment layes, only brush layers, but the colors just keep going crazy like this example. I have the latest version of PS, i've tried restarting the laptop/PS etc, but nothing helps.  

Any ideas?

[Or_David_Shachar]

another example - it also happens around new brush strokes