[chaose]

The best reason is that for example the program used to be called let's CBS 11 News at Five, if the program name is changed to CBS NEWS TEXAS at FIVE the machine is treating it as a new program, and not going to record it because it's still looking for CBS 11 News at Five.  That could be some older systems and depending on pay tv companies machines as well.

Of course! I misunderstood the whole thing. I thought they were referring to a changed channel name, which I now see is silly

A new programme title makes a lot more sense in that context.