I've had that happen sometimes but, honestly, I believe it's a guide data problem, not something under D*'s control. Most companies that provide DVR's with guides buy the data from a third party, and sometimes this data's simply wrong, either because the third party botched something, or because the network showing the program didn't provide accurate information.
Check the info for the program and see if it's labelled "repeat". If so, then ignore what I just said.
Check the info for the program and see if it's labelled "repeat". If so, then ignore what I just said.