In my show calendar, a number of shows will appear up more than once, as if there were/going to be two episodes. But in reality, it's just the same episode, showing up twice. The show that shows duplicates varies.
At the moment my Monday has two "The Cape" episodes. Last time "Glee" was on, there were two of those episodes. There have been other times, but it is never a particular show. The only pattern I have seen is it seems to be the bottom episode on a day that 3 or more shows are airing.