JIRA sends duplicated mentioned notifications when a user is mentioned during issue transition

Summary

When a user is mentioned in the comment during issue transition, duplicated email notifications will be sent to the user.

JIRA will generate one mentioned notification for each action performed:

• If during issue transition, the user is mentioned in the comment - JIRA generates two mentioned email notifications:
• If during issue transition, the user is mentioned in the comment and issue assignee updated - JIRA generates three mentioned email notifications

One of the notification will be generated based on the mentioned user's role in the issue:

• If the mentioned user is watcher/assignee - the notification will be:

  <user-who-triggered-the-action> commented on <issue-key>
  

• If the mentioned user is not watcher/assignee - the notification will be:

  <user-who-triggered-the-action> mentioned you on <issue-key>
  

Steps to Reproduce

1. Create a new notification scheme as following:
   
2. Associate the created notification scheme to a project
3. Add a screen (which contains the assignee field) to a transition within the workflow for project in previous step
4. Create a new issue in this project
5. Perform the transition (for which the screen is added) and in the transition's screen add a comment mentioning someone
6. Perform the previous step again, and this time, during transition update the issue assignee (assign/re-assign)

Expected Results

JIRA should generate only one mentioned notification

Actual Results

For step #5 (Steps to Reproduce) JIRA generates and sends two mentioned notification to the mentioned user
For step #6 (Steps to Reproduce) JIRA generates and sends three mentioned notification to the mentioned user