Correcting purple fringing stopped working in PSE13

Please can somebody help.  I am trying to correct purple fringing using PS Elements 13 which I have done hundreds of times, but now all of a sudden it has stopped working.  I click create a new fill or adjustment layer/ select hue/saturation/ select magentas from the drop down box/ select colour picker tool/  click on purple fringing/ move saturation slider to around -60/ select brush tool/ hold down ctrl and delete to select the mask.

When I now move the brush tool over the purple areas it leaves behind a thick grey line where the brush has been rather than just paint over and correct the purple areas.

Any ideas would be appreciated - thank you!!!!