I think it's also entirely possible that Dolby and DTS have some programming inconsistencies in the way they implement these flags which can cause problems with particular hardware combinations.

Or the producers of the discs aren't following protocol. (I don't have the Harry 2 disc yet, so I have no specific experience there.)

When a PC program has bugs, you don't blame the hardware. Same rules should apply in the computer tech that drives HT these days.