First few discs, I had no audio issues. Now I do. I wouldn't describe it as audio dropoff. It's more that I get very little rear content in bitstreaming mode.
We listened to IV and I without issues, and then I ran Audyssey for a speaker that was moved, and lost rear speaker sound. I fixed the Audyssey setting, and sound still appeared to be turned off. However, using IV as my test disc, I discovered that it was not a total loss of rear sound on bitstreaming mode. Rather, it was infrequent sound for brief intervals. Rear speaker sound doesn't start up when the movie does, there's no rear sound for the text scroll or opening scene. Rear speaker kicks in at chapter 3, approx times 1:57-2:12, 2:29-2:37, and 3:12-3:17. I skipped a few chapters and heard more rear speaker sounds, still infrequent and of short duration with Denon movie button on DTS-HD Mstr. If Denon movie setting is Multi Ch In, there's rear sound all the time, but it sounds like the front sound being sent the rear plus what came to rear speaker on DTS-HD Mstr. Switching to PCM sounds similar, more like an artificial mix rather than being surrounded by sound, as it felt the first viewing when everything seemed to be working. Maybe I still have a setting wrong, I'll be playing around more this weekend. I went through a lot of settings, and maybe I didn't write it down correctly, but at one point I thought full rear sound had returned. When I chapter skipped to the spot again, the rear speaker was quiet except for those few rear effects. A few people mentioned audio troubles after they used chapter skip, so I'll be doing more testing.
For those of you with rear speaker(s) and no audio issues bitstreaming, do you hear rear sound all the time, or just occasionally?