Authorize_net not stopping transaction if ccard info is invalid

I'm finding that the Authorize.net module does not validate credit card information.

I inserted invalid credit card information (wrong expiration date) and Drupal EC proceeded with the transaction. I then did not receive the receipt email from Authorize.net... simply because the transaction did not go through on their end, due to invalid card information.

The module should be providing an error message to the user if they enter invalid credit card information. I believe it used to back in an earlier version of EC.

Any ideas how this can be fixed?