Email ACKs repeating 4 times, every time

We have observed that whenever a user ACKs a message via email, the response and its corresponding actions show up in the logs 4 times over. A sample log is shown below. This happens every time an ACK is sent via email, but does not happen when the ACK comes from a phone or browser.

The reason we noticed is because we have configured an action that sends an email when a message is ACKed, and this is causing users to receive duplicate emails.

Has anyone else seen this before?