Greenstuff does get old
It sounds like you got a old batch, or one that had been sitting in the sun or something like that. I\'d advise tying to get a replacement from where you bought it. The stuff does go bad after a while, although you can make it last longer by storing it in the freezer (I have some thats over a year old and been stored in the freezer the whole time - it behaves like-new!)
--Katie G.
