Why does Zendesk Chat update the assignee or group of a recently ended chat?
When a Zendesk Chat is ended, the integration applies a
zopim_chat_ended tag and updates the ticket to ensure the agent who served the chat is assigned the ticket in their default group.
Since this is expected behavior, we would encourage agents to wait until the
zopim_chat_ended tag appears on a ticket to change the group or assignee. If a trigger is being used to make these changes, the trigger should include criteria for that tag.