I think my S3 has just developed a similar problem. It's an original S3, with expanded HD ("157 Hr HD"), tuning adapter, on TW cable. It had been running fine for years, except for the need to peroidically disconnect the tuning adapter to let "GC" run.
Some time in the last week, even though guide data has been updating daily, it stopped finding Season Pass shows to record. If I go to the "To Do List", all the season passes are shown with "none scheduled". I've deleted and re-added several, with no change.
When I look for shows in the guide, all the data is there, and I can pick and manually record any show. Very strangely, whenever I try "view upcoming episodes", it always says the show "has no upcoming episodes", even though I was just looking at one. Also, when I try "Search by Title", no shows are found (like its search database is missing/corrupted).
I've already tried restarting, and rerunning guided setup. Also, (coincidentally???) the s/w upgraded about the same time from 11.0k to 11.0m. Anyone else seeing this, or have any other suggestions? Thanks.