Since upgrading to 1.3.6 I've not been able to make ANY card payment method validate the date. CC number itself if fine.
Tried all sorts of modules - removing and re-adding etc.
This is now officially driving me nuts!
4111111111111111 exp March 2008
and no other error.
When using a different CC module, it says "invalid expiry date".
I've been and winmerged most things I can think of.