All emails from one particular User goes to only one ticket

[Deleted user]

Hi everyone! Grateful if you can help me solve this issue.
It only happens for one User. Every time the user email on Service Desk, it all goes to one ticket only. It does not create a new ticket. We have tried changing the subject of the emails and other things but it still goes to one ticket. 

Other User when they email, a ticket is created on each email but for this particular user, it only goes to only one ticket.

Appreciate your assistance. Thank you.

[Riley Sullivan]

Hmm this is an interesting one.

The only thing I can think of is either an automation or somehow it is referencing the issue key.

There is a setting for when someone sends an email request that is will add a comment when a valid issue key.

Is there an automation for email requests? 

Both of these ideas are most likely a long shot. So might be worth reaching out to Support. Keep me posted of any updates!