Three identical e-mail notices for one check in session

Steps to reproduce

1. Setup check in notice, add it to a policy and the policy to circ rules
2. Setup a user with email address you have access to
3. Go to check in, and check in an item
4. Close session
5. Check the inbox of the patron to verify that a check in receipt for the session has been sent

Expected result

There is a new e-mail containing a check in receipt for the check in session.

Actual result

There are one to many new e-mails each containing an identical check in receipt for the check in session.