Adhesive definitely has a shelf life, both UV and Conventional. Anything older than 6 months is borderline and 1 year, is tough to believe it will still work properly. If it is still working then your struggling and don’t realize it. Adhesive needs to like the Foil and Fountain solution you are working with and the combination of both is critical. When not liking the fountain solution, you tend to put more down than normal, and when not liking the foil, you struggle passing the tape test and printing on top. When you have the right combination, with adhesive and foil only, you will 100% past the tape test with no residue on top.