Please can someone help me with this?

Issue:  Our ME-SDP will sometimes merge new tickets in to old closed tickets.

or

We will receive a ticket for a new user account, and maybe another 3 user account requests end up in the same ticket even though they have a different subject line.

(There is no ticket reference in any of these emails)

I have a theory that the merge is being done based on some kind of unique email header reference?

I suspect those new hire requests are being forwarded but edited from a previous hire...  Someone is just amending the content.

Likewise if someone is meaning to log a new ticket about an issue they or someone else had previously and they forward it... it can end up merging in to a closed ticket.

I believe I can turn this feature off?

However, my question then, is what about all the times it is useful?  When people start replying to all and adding extra requirements in those tickets.... 

Is this an either or scenario?  Is there anything inbetween?

Turning this off... will mean us merging those multiple replies ourselves?

It will mean when someone forwards a ticket to ask for an update without using the autoreply that has the ticket reference... this would then go in to unassigned?

Has anyone found a work around or alternative solution to just turning it off?

Is this going to be a customer training piece?? eg  "Please do not edit and forward old emails.  Please ensure you email us from a brand new blank email if you wish to log a new ticket, otherwise your ticket could be merged to something old and closed and be missed."

Thanks in advance

Trish