Summary:
Do not send batch notifications when a user is mentioned during a workflow transition comment, is part of the ticket (Assignee, Reporter or Watcher). This would avoid "duplicate" notifications.

How to replicate:
1. Create a new workflow
2. In a transition, set the Event in Postfunction to "Issue Commented."
3. Test the transition, click it, and mention a user (adding a comment) that is also a watcher, or reporter on the ticket.