Vinyl siding is popular around here, and I've seen this a few times. Heavier thickness vinyl and lighter colors are still susceptible to this problem.

The problem with this situation is that the siding manufacturer will blame the window manufacturer. The window manufacturer will blame the siding manufacturer.

The solution is to either screen the sun from hitting the window, screen the reflection from hitting the siding, or choose not to wrap your house (or that portion of it) in plastic.