Hello,
we also want to select a default group on ticket creation, so we created a workflow like the one suggested here. At a first glance, it seems to work, the choosen group is selected in a new ticket. But if the group is changed by the user, it jumps back to the default value after a second.
This ticket also describes the issue (link to video included): Core Workflows - Ticket field - Set initial/default value
Best regards,
Matthias