I have only seen a slight amount of this and only on one of the short pieces that makes up bin extentions. Never notice unless up there scrubbing with soap and water. I even had to paint a set of extentions for a 62 that came in without. I cleaned and roughed surface. Then I painted with corporate silver straight out of raddle can. I was surprised how good the match was and years later it is still sticking. I fully expected to pull them back off after harvest and have them profesionally painted. I have seen a couple machines with paint dulling a bit and mainly on top surface of engine hood. I suspect this is from machines shipped during salty roads and never cleaned when received or sitting for long periods with damp acidic wet dust working on paint. I'd suggest to keep machine free of dirt build up as much as possible especially if wet.