I have searched and conducted experiments, that what caused ticket visibility to change from private to public in Zendesk messaging is when the ticket has passed 10 minutes since the ticket was created, but the ticket is not picked up by all agents (still: NEW).
but I found some tickets "ticket visibility" changed from private to public before 10 minutes from the ticket was created.
so i want to ask actually what caused ticket visibility change from private to public in zendesk messaging?