We have a customer that we email with regularly and they work out of Salesforce for their communications. For a long time, their replies to our tickets would not thread properly due to the RFC standard that Zendesk uses, as noted here. The customer made updates to their Salesforce environment to resolve the problem and the issue now works just fine.
We recently implemented Side Conversations and communicate via email with them. However, the replies to our side conversations are not threaded there but are creating brand new tickets (very annoying!) But the replies to tickets still thread without issue.
Is there a way to resolve this? We did not expect the threading logic to differ between tickets and side conversations.
Thanks for sharing your experience—it's definitely frustrating when side conversation replies start creating new tickets instead of threading properly. Since you mentioned this behavior changed around mid-December 2024, it could be related to an update in Zendesk's email threading logic or how side conversations are processed.
At this point, the threading rules for side conversations do differ somewhat from regular tickets, which can unfortunately cause these new-ticket creations on replies. I’d recommend reaching out to Zendesk Support to see if there’s any recent change or workaround specific to your account or environment.
In the meantime, keeping an eye on product release notes and community updates may also help identify if this is a known issue being addressed.
Hope you get some clarity and resolution soon!