Never been covered,as far as I'm aware I havnt spilt fuel on it i never fill the tank to the brim.made that mistake on my gen1 and it went yellow but didn't cause a reaction..I'll speak to them Monday like you say worth a try at a warranty claimHas it ever been covered? Wondering about some form of adhesive eating at it.
Overfilled the tank? Petrol can lift the paint....
Just thoughts, I'd certainly try for a replacement if I could.