i have 2 suggestions as well, I also hone using a coticule with the dulicut method, I use half strokes during a dulicut, not full X strokes

if you keep "diluting" your slurry to much you're basicly honing on water to long, which can result in a foil edge, resulting into the issues you've discribed

if the affliction turns out to be contagious and starts spreading to other razors in your collection it could be caused by some coticule garnet rolling around on your 'plain leather strop'