diff --git a/academic_sale_subscription/models/crm_lead.py b/academic_sale_subscription/models/crm_lead.py
index 6de7c784..9489c9fc 100644
--- a/academic_sale_subscription/models/crm_lead.py
+++ b/academic_sale_subscription/models/crm_lead.py
@@ -16,3 +16,11 @@ def _create_customer(self, with_parent=None):
                 with_parent=with_parent
             )
         return super()._create_customer(with_parent=with_parent)
+
+    def _message_post_after_hook(self, message, msg_vals):
+        """Override to prevent automatic partner assignment when posting messages through chatter.
+        In the standard CRM behavior, when you send a message from the chatter to a recipient
+        whose email matches the lead's email_from, it automatically assigns that partner to the lead.
+        This override disables that automatic assignment.
+        """
+        return super(models.Model, self)._message_post_after_hook(message, msg_vals)