My DVD player is about 3.5 years old (Sony). It happened while watching Minority Report and Mission Impossible II. I know what your talking about in terms of flagging DD and non DD material. My old Yamaha receiver use to switch back and forth without any audio disruption.

I will try to watch another movie today, will be hard with the two football games, and pay more attention to the LCD screen to see what it switches during during the audio drop outs.