If I raise a case, e.g., no 12345, for a customer and then send an email from the case to the customer, the case (email-to-case) ref. is included in the subject of the email. The recipient is also a Salesforce user with a different org with email to case and now they have a new case set up via the email to case. They then reply and their email to case inserts their case ref in the subject line. Will this be logged as a new case in my org or will it be attached to my case number 1234?
Best Answer
I have hit this in our live instance. One of our suppliers also use email2case and what we have found is Salesforce makes a cursory check to see if a threadid is present - I presume by regex because it does not look for a thread id that matches the specific org. If it finds one it will NOT add a thread id.
So from my experience (steps to recreate):
The only work around for step 3 at the moment is getting the user to manually copy the thread id (generated via a formula field) into the body of the email. This means both SF instances recognize the email and associate to the correct case.
I've spoken to SF support about this and they confirmed the above. They are treating it as a bug but with no timeline on a fix. The bug number is: W-891382. I'll chase them about it again now.
Update response from SF Support (as of 15th July 2014): I already checked your issue with our higher level of support and as of the moment R&D is still working on it and does not have any type of tentative time frame on when it will be fixed. Rest assured, we will notify you as soon as there is an update on this issue. Please be informed that I tried to contact you but it routed me to your voicemail. If you're available today, please send me an email so I can call you back. I will be looking forward to hear from you.