I am using "4-5 PP Skin Undereye Circles" brush and am having some issues. I was able to use it just fine on one photo. Now on another I brush the area I was edited and as soon as I let up on the mouse button, the brush Effect changes by itself to "4-5 Add Darkness". The brush mask is still on the photo but the eye circles are not reduced. I also see in the History "Delete Adjustment". I've tried restarting Lightroom with no effect. I've tried removing the brush files, restarting, and adding them back with no improvement. Any idea why this brush seems to have stopped working?