Sticky expired film

I have recently (2-3 weeks ago) bought a lot of expired films and they stayed in my bag since then.

I wanted to use one of them (color plus 2007/2008), but the film was very sticky and almost all parts of the film changed their color.

The day on which I bought them was rainy and films were not stored in boxes, but i put them into the empty canisters as soon as possible. (but other films are normal)

Can it be because of the water?