Did it record absolutely nothing, so that there was no entry for the show in the Now Playing List? I'm OTA only, and when that happens to me (due to a channel being off the air) the TiVo will try to pick up the next showing on that channel or (if there are no more) the next showing on a lower priority season pass for a different channel. It takes a little while for it to notice, but 2 or 3 hours should be more than enough. It won't record from a different channel if there is another showing scheduled on the higher priority channel, even if that isn't for another day or two.
Being OTA only, I wish the TiVo would keep track of error counts and allow the next showing of the same episode to be recorded automatically if the uncorrected error count exceeds some threshold. Poor reception conditions (storms or whatever) can cause me to get a recording that is there, but too glitchy to be viewable.