I know it wasn't the layer change because the picture freezes or pauses during a layer change, but during this, the picture was normal and only the audio was paused. Plus there is only one layer change and this happened a couple of times during each movie.
Actually, while watching the first moving I swear I saw the display switch to DD-EX for the 1 or 2 seconds and then back to DD. I then realized that I never switched the rear speakers to none and thought that was it. But it still happened after I made the correction.