I've had a bodyguardz film and a bumper on my phone for over a month and encountered no such problem. There is no "lifting" anywhere.
Did you put on the bumper immediately or not too long after you installed the film? If thats the case then I can easily see the film lifting up since the pressure applied by the bumper is probably enough to lift a moist film.
I had the same problem with my bodyguardz and I waited at least 48 hrs after I installed the bodyguardz before I put on my bumper. I've since switched to SGP on the front and bodyguardz on the back and I'm not putting the bumper back on.
yes, I had the film on for a month before I got my bumper. It's annoying that I have to constantly push back down the edges when it lifts. I've also notice if your phone gets hot, the film gets soft and can lift at the edges too.
I think I'll gonna try the powersupport films. Hopefully they won't lift since its a more sturdy film.
The film will be pushed up on both ends in MOST cases. iFrogz, IS, BodyGuardz and even the Incipio film have ALL failed my test. iFrogz has agreed to replace their screen protectors and explained that their cases are being re-manufactured to allow for their screen protectors to fit THEIR OWN CASES! Their customer service SUCKS, b/c it's been over a month and I've not received the coupon or credit as they had promised...
Yeah, I get film lifting on 2 different films I've tried. I think I'm going to end up cutting the next one down so that it's covering the screen only. That's the way the film on my 3G was, and I never had any problems with it.