he commented that is seems like the contents of the product were reacting adversely to the packaging
That was my first thought as I read this. The hydrocarbon/oil material is probably dissolving glue used to seal the foil packet. If it is mylar rather than aluminum foil a similar degradation is probably taking place. I think I have some of these stashed away. I'll take a look at them and see what I can figure out.
-Blast