Another example is a user's password - the change password screen claims a password cannot exceed 20 characters, but it accepts more. I'm not sure if it silently truncates the excess characters, or actually uses them all and so the stated limit is false.
If it's the first case, it's pretty important issue then. I had this on one site, after registering I simply couldn't login! So I've changed the password, and still I couldn't login... And then again...