According to a DIRT team response, it is not a bug. Some channels are blocking watching recorded events if you no longer subscribe. The problem with the answer given is they said it applies to all receivers. I never have had one program not play back on a channel I no longer subscribe to on my 612 receivers. I don't know if the DIRT response is correct but just can't be blocked on some receivers, or if they were given wrong info.
Supposedly software updates have made the issue better (specifically with EPIX recordings) so that would seem to indicate to me that it is a bug and not in fact intentional. Not to mention the fact that the older ViPs don't have the issue.