I have the Denon AVR-1312. I had a buddy mention that the source could maybe change the setting. I wish there was a way to override it. Sometimes it doesn't change back.
Yeah, I think this is the situation. My pioneer elite, in direct mode, will show dts on some shows, then swaps to stereo on commercials or on previews. But, it always changes back when the show comes back on.
It is the source material making the change, as different items from the cable box are recorded and distributed in different formats. Really not much you can do about that, no way to override how the material is distributed to your cable box. But, it should be changing back automatically, so if not then you may have a problem. Maybe try running in a mode other that direct?