Setting up a trigger to only fire on new replies to a ticket

Our trigger that posts ticket-updates to Slack fires way more often than I think it should.

I only want to see when a new comment is added to a ticket, either by the end-user or by an agent.

Here's my trigger condition:

but it still fires when, eg, the autoreply bot sends out some suggested fixes and the end-user visits a helpcenter article:

What am I missing?