I have been making the same recipe of fondant since starting to make cakes Jan 2011.
Within the last few months it has intermittently not been right. most of the time it has been perfect!
I thought it may be the weather but I dont recall thia happening last year at the same time.
I am using the same ingredients 7g gelatin powder with 1/4 cup water, heated in microwave, add 26g (2 tbsp) trex, 100g glucose, 5g glycerin optional 5g flavouring 2lb sifted icing...