Contaminated metal??

[dme922]

I have been having an issue with the paint on my bed sides since about two months after i got it back from the shop. It looks like little bumps in the paint and the shop originally told me it was solvent pop and it would buff out. They buffed it and it came back shortly after. Then they decided to sand down into the paint to see how deep it was. I think he sanded it all down to the epoxy primer and repainted both sides and once again it came back within a few weeks. Now they are telling me that after sand a few spots down to the metal that the metal is contaminated with rust. Only way to fix it is with new bed sides. The bed is in nearly perfect shape no holes or anything and to see this rust he is talking about you have to use a scope. Has anyone heard of such a thing?