What do you mean by this? DTS is a packetized format, and the receiver is nearly guaranteed to have a buffering DAC. It doesn't matter how much the player vibrates. Even if there were something to this, it wouldn't hold up given the fact that he's playing at very low volume levels when this repeats.
It sounds like the receiver is getting confused and decoding the stream incorrectly (probably thinking it's PCM). I'm not sure why this would happen on certain players at the same time, though. This is a common problem when you try to play DTS encoded CDs in a system that doesn't support them. The player simply reads the data off and treats it as PCM samples, which leads to some very, very loud noise. This does not sound like the receiver losing a lock on the DTS signal, though, since it should be more intelligent in that case, giving dropouts. Have you tried a different HDMI cable? Perhaps the overall bitrate is spiking in the area you're having problems and exposing a weakness in a poorly made cable. Doesn't seem too likely, as I'd think the overall bitrate of a video + 7.1 PCM audio signal would be higher than video + DTS HD MA.