OK, I had a weird problem I've never seen before.
Sometime after ~12:37AM, I noticed that my TivoHD was only recording 1 show (1 red light on on front of Tivo), not 2 (Jimmy Kimmel & Late Late Show -- I record all of the late night shows but FF through 99% of it).
I tried to tell it to record Late Late Show.. but it then told me I'd have to stop recording Jimmy Kimmel. That made no sense, so I went looking around for other issues (I thought maybe there was some program going to record at ~1AM via a wishlist)..
The Tivo *thought* it was still recording Letterman's show.. The To Do list & Now Playing lists still had a red icon on that Letterman episode.. But it was fully there, and 1:04 long just like expected.
Oh, and I forgot to mention that I did have a 1 minute recording of the Late Late Show, so this 'confusion' somehow started after the new recording happened.
The Tivo wouldn't let me actually stop its phantom Letterman recording (choosing stop recording did nothing).. A later dual-recording happened successfully, but when I checked it, it still thought Letterman was recording.
This morning I rebooted the Tivo, and left before it finished.. so hopefully it's dutifully recording tonight's stuff.
Anyway, just a tale of a weird bug I'd never seen before.