Many items derived of various combinations of plastics (chips) and rubber adhesives (tapes, sticky pads, etc.) will "off gas" for many many years after being made. it is an imperceptible action not noticed.
Also it's fast as what happens sometimes with fishing lures thrown into a tackle box, found a week later melted into the tray because they were chemically reactive to each other!!!
I wouldn't glue, tape, temporarily attach any "non replaceable" collectable item unless it was expendable.
I'd try encasing it in an expendable capsule then glue/tape to hold in position , or frame it in a holder slotted for the pieces..

Just a thought...

Gabe Dobos LM 4143 - 180
On the Detroit River