Here's my idea ....
Eliminate all programming which is responsible for still image output. Only write firmware for movie footage. For the time being don't worry about the Epic being a movie camera and a digital still camera. Only include the code necessary for movie footage ... and see if the bug remains. We can live without digital stills ... there are other solutions for that at this time. No one would buy an Epic if it didn't have movie capabilities, that's what we all want.
Maybe have two separate paths in the firmware and a user choice selector ... one firmware path for stills ... and another firmware path for motion ... make it totally separate logically. Produce the Epic with movie capabilities, with digital still capability to follow .... (the fact that I know nothing about the problem won't stop me from offering solutions)