UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.89 Safari/537.36

Steps to reproduce the problem:
1.  Go to web-payments-sample.firebaseapp.com, and check out
2. Add a credit card that is already expired
3. Add is successful

What is the expected behavior?
UI should validate my credit card expiry date and stop me from adding.

What went wrong?
UI should prevent me from adding a credit card that does not validate correctly (a credit card that's past its expiration date being one).

Did this work before? No 

Chrome version: 53.0.2785.89  Channel: stable
OS Version: OS X 10.11.6
Flash Version: Shockwave Flash 22.0 r0