Unable to reply to Jira emails if project's notification address was changed

Issue Summary

If the Project's notification email address is changed, internal Jira users will not be able to reply to Jira notifications

Steps to Reproduce

1. Go to any Jira project > Project settings > Notifications.
2. Change the notification address to anything other than the default one. Example: project@site.atlassian.net
3. Trigger a Jira issue notification to yourself.
4. Reply to the notification. Notice that the reply will be sent to whatever you've set in the notification scheme, instead of jira@site.atlassian.net (Jira's default incoming mail address)
   
   

Expected Results

Your email is added as a comment on the ticket.

Actual Results

Your reply will fail and a bounce message will be received.

Notes

• Jira should be adding its default address (jira@<site>.atlassian.net) as reply-to in the notification email header.
• This completely invalidates the following KB: Configuring Jira to send emails on behalf of your domain

Workaround

There's no workaround other than using Jira's default email (jira@<site>.atlassian.net) as the notification address.