I have a HWS that had a similar problem saving a recording for a PTAT program a year or 2 ago with the last show on CBS on Sunday nights. It frequently saved the first PTAT program, 60 Minutes, instead.
I found that I could force a timer during PTAT to record outside the PTAT system by going to the timer screen, selecting that program, selecting Timer Schedule, then selecting each PTAT program listed (which showed as Skipped: PrimeTime Anytime Event) and selecting Restore Event. This made the timer create the recording outside the PTAT system, so the recording wasn't ruined by the PTAT save recordings process. I had to remember to change each recording ahead of time. I don't know it you can do this on an H3. The commercial skip function appeared on the 8th day just like it normally does for PTAT programs from CBS.
You could probably also fix it by dropping ABC from the PTAT system or dropping the day of the week that the problem is occurring. You would need to create timers to record everything you wanted to see that is no longer saved by PTAT, so I wouldn't do this unless you are having a lot of problems. I watch all 1/2 hour programs that I want to see before they are automatically deleted by PTAT, and only save programs that are 1 hour or longer.