Weak/bad signal. The red recording light will come on and stay on for the duration and will be in the my shows list whether a recordable signal is found on the channel or not. If it gets no signal at all, there will be no recording to save in the my shows list so that disappears.
Just this past friday it happened to me for the second time in 2.5 years.
Did you check the history?
discipuli nostrum bardissimi sunt.