Hi. I have had my 2013 848 Evo Corse SE for a few months and am about to get my third tank installed. When I first got my bike the tank was beautiful but after 3 months I noticed that on the front of the tank the aluminum. Was getting almost what I would call a "rash". The brushing looked off and discolored. Got it replaced and same thing happening. Anyone else have this happen and know the cause ?