I had this same problem, and it was especially a pain because I have several Timers that are Search and Record so that they catch the program or movie over all the channels that it airs. This meant, I would have MISSED several recordings if I had not created short-term standard Timers. In other words, my TV shows were indeed on the guide and NEW, but checking my Timer Schedule for the Seek and Record Timer would show no programs scheduled. I first noticed this last week. This lasted for days.
THEN, as of 2 days ago, I find that all is working as it should. All my Search and Record Timers show episodes will record as scheduled. I have deleted my temp timers. Also, the search function works as it is supposed to now, as well, as it did not before.
Don't know that the problem was, but glad I do not have it anymore.