Warped vinyl siding - can paint cause this?

[Evan C.]

I'm in the final stages of finishing a rehab and the vinyl siding has developed a recurring warping issue that I can't diagnose. The home is in NC and the siding in question faces west. It's the only side affected. Some, but not all, of the siding was replaced in the rehab. Contractor thinks it's the paint, but that doesn't seem to explain why it's only this side. He was able to largely fix it, but now the PM is saying it's back. My theory is maybe an installation or moisture issue, but I really have no idea. This first happened in May, so we hadn't hit the major heat yet either. The photo is from the first occurrence, in late May. 

Anyone seen this before? 

Warped vinyl siding west side

[John Teachout]

I've seen this before and it's not common. My thought is that the siding is defective. Common causes are a nearby bbq grill, burning debris or leaves too close to the house, etc. But if there's no external explanation, it's probably just defective vinyl. In the cases I've seen, the vinyl wasn't old.