Onion skin causing my sprite at a lower and lower opacity to appear once i erase it

Every single sprite i draw fills me with anguish if i ever have to erase something because of this glitch. I can’t find any fix. It just take more than one click. I don’t know where to go to fix it or if it’s even a bug or not. I just need a fix. It doesn’t even erase it, it just changes the opacity.