Mystery of the Missing Decal Solved

Years ago I bought a G.I. Joe Rapid Fire motorbike model kit at Yaohan (Now Parkson) and found that the kit was missing its decals. The decal sheet was there, just that there are no decals. Funny.

Recently while shifting my model kits collection, I decided to inspect my Revell Batman Forever Batwing model kit. The kit is fine. The chrome part is still shiny. Then I saw the decal sheet which was supposed to have the batman Forever logo. Parts of it goes 'invisible'. Check it out.
Not sure what caused it. Our weather perhaps? So model kits collectors - beware.