It's possible your cable company intends to delete the channel.
The listings source that TiVo uses may have been notified about the deletion, and the result is it got deleted on the date the cable company said it'd happen...
...only the cable company ended up not doing it on that date.
Others have had the same thing happen, and not just to "lesser" channels like GSN.
Keep an eye on it.
If the channel continues to be there but the TiVo keeps thinking it's not, maybe the listings service got something wrong. If they did, you can report the lineup error to TiVo.
Click on that link when you think enough time has passed, and give them the info.
They'll likely double check, and if the deletion was a legit error, TiVo will have the channel restored in just a few days.