Smell it, the mold will smell earthy and the kahm will smell yeasty(taste yeasty funk) After scraping ,wipe with a vinegar moistened paper towel.
I don't know why but my pepper ferments are the only ones that get kahm. Yoop, it even forms on the bag of water,WTF. I clean it off( toss the grape leaf), it comes back one more time ,then it's packaged and refrigerated, no more kahm even after a year.
It's like the little bit of frass you see in organic brussel sprouts, don't tell anyone and they'll never know!