P: Bleeding color with Healing Tool

Lately, I am getting different (poor) behavior when using the spot removal tool in heal mode on the edge of an un-cropped image.

For example: if I have a mostly black edge of an image (say, a groom's black tux jacket), with a little bit of white along one small portion of the edge (say, a crease in the jacket and I can see a little bit of white wall behind the jacket), if I spot-remove the white, formerly it would completely wipe the white out, leaving only black (or shades of black, if you will).  But lately it's acting as if I'm not surrounding the entire white area with my spot, and leaving some white blurry bleed in the healed area. Doesn't matter if I define a smaller heal area that's just beyond the white area, or a huge heal area that's far beyond it... circular or un-circular spots... and no matter where I move the sample area around.

I just started noticing it in the past day, but it may have been around longer.  It's happened on multiple images, in different situations, and I have been careful to make sure the image is not cropped or lens-corrected or transformed... so I'm definitely not picking up any area/white outside of the visible edge.  It never used to do this, so I believe it's likely a bug.