Some channels (eg Sony movies but not excluded to) often use the same code for each time a film is broadcast. This means that, if you are not careful, you can end up with the same film being recorded several times (with no series link necessary). Same can happen with some series linked documentaries (Ed Stafford as an example) where the whole series can be repeated several times over a few weeks and you can end up with 30 episodes (6 repeated 5 times).
This has caught me out quite a few times.