The order in which you select data columns in Aha! when creating a Pivot table will affect what data is shown. For example, if you select Feature name and then Release name, you will see data for only releases that have features. You will, in essence, think your report is missing some of your releases if you only created a release placeholder.
The solution in this case would be to select Release name first, then Feature name.
This logic can be applied in other scenarios as well.