I was looking through my CHUG collection box recently and noticed that the Reveal the Shield stickers (eg Jazz, Perceptor, Wreck-Gar) were no longer working.

Rubbing it did no change, I put one briefly in front of a bar heater also no change - just a black ambiguous symbol.

Was wondering if this was a thing that affected other's RtS collections?

(I didn't check my first year Classics toys or my G1 toys either - just happened to be all RtS toys.)