Two weeks in a row I've been watching Once Upon a Time
and had the recording frequently do some weird jumping: you're watching, then it jumps back a few seconds and repeats what you just saw, then it jumps forward to catch up with where it should be (skipping stuff). Last week it was annoying; this week it made the show almost unwatchable at times.
A month or two ago we had some weird semi-seconds of blackness in recordings every once in a while which might or might not be related.
At least for the 6 or 7 shows we saw in the last week, this was the only show doing that, and it's possibly the only show we saw on that channel.
We're using Comcast (unfortunately) digital cable.
Any ideas whether it's a source problem (e.g., the cable channel), a cable card, a tuner, a drive ... ? The Series 4 is just a year or so old and the cable card is brand-new (we had to replace it) so I'd be pretty shocked if it was the hardware, but ...