I have two simple Clustered Column Charts filtered to show me the following
Chart 1: Everything from Category X, Filtered by Container on a TOP 5
Chart 2: Everything that is NOT Category X, Filtered by Container on a TOP 5
Chart 1 is correct and shows me a top 5. Chart 2 only shows the top 4 items, However if I change the Top N selection to show me a top 6 instead, it will display 5 items. The pattern continues, Request a top 7, and you only get top 6.