I have two customers A and B, I send a message from the contact chatter to A, A replies to me and cc to B, after B receives the email, he replies to A and cc to me, at this time, A will receive 2 same emails, one is a normal reply email, one is a notification email sent by postmaster-odoo, If continue to reply the email, A and B will even receive 3 same emails, including 2  notification emails，I have set Notification Handle in Odoo in preferences, and cancel Default in technical-Subtypes-Discussions,it doesn't work at all.

Please help me ,Thank you very much ！