Playing against the same league and cup opponent in a short period of time

For years now I notice that my team very often plays against the team I play in the cup in the league in the same week. It happens too often to be chance. I had it against Malaga and now again against Getafe in the next round. I actually play Getafe three times before I play against any other team. Now when I think of it, I wonder how this can be? The fixtures are arranged pre-season, so how is this possible? Is it because of postponed matches that both teams have their match postponed at a date around the cup match?