ntozier yes , The cross domain user who is replying in the ticket is already a collaborator , but new ticket is created for replies made by them.
Also same domain users if replied within 3mins or less , it is also creating as a new ticket. So totally two types of duplicates i am facing. Monthly 1800 to 2000 duplicates creating and facing lot of issues while presenting the monthly report to the management.
Please help for this asap.