Recordings stopping before end of show.

[Amused]

Twice this week I've discovered recording which have ended too soon. Chuck on Monday only recorded 3 minutes which initially I put down to a glitch in the EPG (I thought maybe the end time had been set to 2203 in stead of 2300) but then last night Shark only recorded for about 34mins. Most shows are aired again so I can re-record them later (I successfully recorded Monday’s Chuck last night) but it's a nuisance.
I've attached the logs. Anyone got any ideas what might be causing it?

[stustunz]

bad signal i would say

[Amused]

Could be bad singal on just that MUX. I thought of bad signal before but discounted it because other recordings happening at the same time were fine. I'll run ScanBDA again and see if the sig. quality has dropped.