They don't necc warp per se, but I found some of mine had no gaskets at all around the moving window part. Some I didn't notice had a bend to them, but they haven't done much else, meaning they were prob like that from day one in my case. One part of the non-moving window part had to be re-glazed as it moved somewhat freely in the window frame.
The HEHR windows are POS. You can ask the factory for warranty help on it, but a year out of warranty, best of luck with that, as they don't do may out of warranty type things.... once the two years is up, it's up. Not sure about HEHR, but if they are like most, the bureaucracy is a mile long.
Computers manufactured by companies such as IBM, Compaq and millions of others are by far the most popular with about 70 million machines in use worldwide. Macintosh fans note that cockroaches are far more numerous than humans and that numbers alone do not denote a higher life form. -NY Times 11/91