when XYZ is the reporter of a ticket that he will automatically be receiving mail triggers.

[XYZ User]

when XYZ is the reporter of a ticket that he will automatically be receiving mail triggers when there are changes on that ticket.

[Alexey Matveev]

What is your question? You mean that you do not want the reporter of an issue to receive mail? Then you should change the project notification scheme. You can read more here:

https://confluence.atlassian.com/adminjiracloud/creating-a-notification-scheme-776636401.html

[XYZ User]

I do not know for sure what the expected behavior is but I would expect that when person_xyz is the reporter of a ticket that he will automatically be receiving mail triggers when there are changes on that ticket.

[Alexey Matveev]

Then you should go to the project notification scheme and make sure that for the Issue Updated event the reproter is set. By default the reporter must be there after installation.