Alerting a user(@mention) via Automation adds the user to the Request Participants as well when the issue is created from Customer portal

Issue Summary

When you have an Automation to Alert user (@mention), and when you create an issue from the Customer portal, after the Automation runs and adds the user @mention, the same user is getting added to the 'request participants' as well. The same behaviour is not noticed when you create the issue from Jira.

Steps to Reproduce

1. Create an Automation similar to the below -
   
2. Try creating an issue from the Customer portal which satisfies the Automation rule, this will add the @mention user automatically to the Request Participants
   

Expected Results

The user is just added to the Comment as @mention and notified accordingly.

Actual Results

The user is getting added to the Request participants as well.

Workaround

Disable the mentions on customer portal feature. Please note that this will disable mentions for all the customer portals. The alert automation will work as intended. To do this please add the below dark feature in your instance -
 To disable the portal mention feature : sd.customer.portal.editor.mentions.disabled