SylwesterD

Thank you @MEB and @Ron P. - changing blending mode to normal resolved the problem - how I missed it???

Nothing change when the Protect Alpha is on or off.

You are right -the problem is related to Invert adjustment. Screenshoot below: blue figure, HSL adjustment inverted (plan to desatrurate color). Painting a white brush on the figure should desaturate the color - nothing happened.

Yes, exactly.

When I invert a layer and try to use white brush to revel the effect of the layer nothing happened. I checked and updated all drivers, in preferences switched off the hardware acceleration, did reset studio, reinstalled the affinity. NO results.