spot healing brush tool creating random yellow outlines

I have been using the spot healing brush to get rid of some black bits along the edges of a layer. It was working yesterday but I come back today and suddenly it's leaving yellow outlines around the edges and I can't figure out why. The image itself is red. I've tried reseting the tool multiple times and closing/reopening PS but nada. Why is it doing this? Is there anything I can do to make it stop?