Missing recordings, no trace

We have two HR24/500s with a swm setup. Several times, recently, we've had recordings on channel 603 (NBC Sports HD) disappear. We've both seen them on the todo list, but when we go to view it (typically later the same day it was recorded), there is no sign of it in the list or history. Today's was the Tour de France from 8:00 to 11:30; it was recorded in the Living room as scheduled, and had been scheduled in the family room with 30 minutes additional. The Living Room recording was there (and fine), but there is no trace of the Family Room recording.

In a few cases (a few weeks back, not sure if before or after the 5d2 upgrade on 6/21), the recordings have shown up with a message similar to "not recorded because channel is not available".

We've only noticed this on this one channel -- the the program is always "Cycling", but that's all we record from 603.

Is this a known problem? It's not something we've noticed with other programs/channels.