I don't believe that the humid conditions in Florida contributed to the lifting inlays. Every Florida c&s I have that was from the 1911-1940s have perfect inlays (The Floridian and several BPOEs). In fact I have not seen any Floridians with bad inlays.

However, ALL my pre 1911 have lifing inlays (like my famous jockeys and the union jack/old glory 1895 flags). The early chips mathed paper with celluloid. There is no strength in the paper. The celloid, like a wet piece of wood, would cup when it dried out.