Well, I'm sorry to say the mystery of Cinavia continues. When the backup was played back on a PS3 attached to a receiver (HDMI DD 5.1), the audio was muted after 20 minutes (did not matter if it was FF or waited the entire time), but when played back via PS3 attached to a TV (via HDMI stereo), the sound was not muted for the entire film.
I am sorry if it seems as if I am being cryptic, but I don't have any additional information to share, not because I don't want to share the information, but simply because I am completely baffled by their protection. The only fact I've been able to gather so far is, it is in The Losers and Repo Men, and no, I am not sure what region the original disc is from. Sorry.