Did you seal them first? All of the aftermarket HL's i have encountered were in definite need of being sealed with some RTV first. It's easy to do and doesn't cost much or take long. In fact, AM has a little how-to on it here.

I have a cheapo set i bought used from a member on here, can't remember who lol. They are only about a year old and the clear coat is already peeling. However, I am starting to wonder if i didn't have something affect my entire car, as my clear coat on my hood and fenders is peeling as well..weird.