Painted bare aluminum roof and it stayed discolored.

I just started painting a friends aluminum roof that hadn't previously been painted but was slightly discolored. The discoloration was a very light color but after spraying it the discoloration is almost more visible. I went to Sherwin Williams and asked them what to use when buying materials. The paint is DTM Acrylic Coating and I sprayed it on. I've been painting for many years but haven't ever had this issue. The sun was on it at one point and I'm not sure if the heat had anything to do with it. I live in Florida. It became more noticeable after a second coat I even tried rolling a couple panels a third time to see if it would help but to no cause. The lady who's house it is she's selling so i'm slightly worried about it just because I can't seem to find a solution.