Blame the universe not the tank!
I had it where the tail lights are supposed to line up with the tail section. Initially I thought it was left over wax, but it turned out to be powder from the abrasion of the light rubbing on the tail. I wedged a small piece of electrical tape in it. You cannot see the tape, but it maintains spacing. When I get around to tearing off the pass pegs, I will check to see if I can realign it properly. Pass seat did the same too. Another piece of electrical tape cured this. Sorta sad, but it seems like dry fit, remove, tweak should have been done to prevent this. You know this would show up on pre prod bikes, so no excuses Ducati.