Dynamic Date Tag

I used one of my rule's custom tokens (beginning date) to create a dynamic tag, which is simply to contain the date's year.
However, after running dozens of files through with various beginning dates, all of the dynamic tags evaluated to 2016.
Am I doing something illegal? or expecting something unattainable?
John V
However, after running dozens of files through with various beginning dates, all of the dynamic tags evaluated to 2016.
Am I doing something illegal? or expecting something unattainable?
John V