Lost AC3 playback from Handbrake videos

I updated (using the Maintenance menu) to the newest nitoTV a couple days ago and now my Handbrake-encoded .m4v videos won’t play back in 5.1, only in 2-channel Dolby Surround. It was working fine prior to this update… even tried to remove nitoTV and reinstall but same result. No problem with 5.1 playing the same videos in XBMC or even playing Apple-purchased ATV files. Any ideas? I’m thinking something had to change in nitoTV but sadly not for the better.

Oh, and I seem to have lost the ability to play back my DVD disc images as well… it appears to start and then just gives me a black screen and goes no further. Not sure how long that’s been going on since I mostly watch those via my Asus O!Play box these days since it’s easier to stop and get back to the same point.