A partner company uses Zoho as well as we do. Whenever I create an issue in their system and I get an answer from them, my Zoho automatically merges their ticket recently created with a ticket of my own system matching by ticket number. As result my own tickets end messed with wrong merges.
The only way to prevent this funny behavior is to use a different email in my partner ticket system, or maybe I'd like to know if I can disable the automatic merge. But it might be an improvement if Zoho checks the subject or other fields before merge automatically the tickets.
Best regards
Santiago