Proper email threading is well described in https://www.jwz.org/doc/threading.html and relies heavily on the In-Reply-To and the References headers of an email and, if all else fails ( and this is extremely IMPORTANT ), on the Subject of the email - a technique called threading by subject.
"Threading" means that when Freshdesk receives a new email it has to decide if it belongs to an existing ticket ( in which case it add the email to the thread of that ticket ) or not ( in which case it generates a new ticket ).
We have a good number of customers that use exotic mail systems. These systems send replies that don't provide proper In-Reply-To and References headers ( if they provide them at all ). We also have customers that compose new emails and just use the Subject of our reply as the Subject of their response email in the belief that this is enough.
Judging from the fact, that other Freshdesk users also mention such cases, I believe that my problems are not unheard of but just more prevalent.
We have past experience with systems that used threading by subject and could handle these emails. My understanding from testing competitive products, is that a number of other helpdesk platforms, also implement decent threading by subject.
In most cases, the threading by subject implementation in helpdesk platforms relies on searching the Subject of the incoming email for a string that can be matched to a ticket number. For example, it can be configured to look for the first occurrence of SometextSomenumber and use Somenumber as the ticket number. Example Subject of a customer reply, with COMPX used as Sometext:
Subject: Re: [ Case: COMPX674591 ] My gizmo is not working.
A threading by subject system that works as described above, will conclude that 674591 is the ticket number and, if a more reliable match cannot be made on the basis of In-Reply-To and References headers, will add the email to the thread of that ticket.
My understanding is that Freshdesk does not implement threading by subject ( but I would be very happy to be proven wrong ). I REALLY want Freshdesk to implement threading by subject ( and give the admin the option to enable or disable this feature and select the Sometext value they want ).
If you are a fellow Freshdesk user that has faced problems with multiple tickets been created when customers with problematic email systems reply, please support this feature request.