Video:
I maked a not listed Video (01:30s, english, with subtitle):
https://youtu.be/MGtb2zOQdYM
Please watch this because thats the best explanation.

Text:
When you want to detect the AGE value of an dropped item, there is no problem, BUT when you drop the Item from your Inventory (E and drag it out of it) THERE ISNT A AGE!
I detected this while MapMaking.
Watch my Video of the Bug, its better than a text!