Another thing I have discovered is that most of the "passes" are linked to the app they came from and when that is updated then the pass updated. For instance my Starbucks pass won't update the balance unless I have the Starbucks app open AND update the balance there. My AA account pass won't update miles unless those are reflected in an update from the AA app. Same goes for my Marriott pass and app....
However both my iTunes pass and my Walgreens pass are very stubborn. I can't get these two to update unless I remove and re-add them. I am not going to do that, I agree with you this seems broken in iOS 10....