Since the dev site reset:
Administration: Create user - Technician
Clients: Create test client with minimal information
Create two assets with minimal information
Create ticket assigned to Develop User using client and one asset
Enter the ticket - Edit - Change Assign to: Develop User to Technician - Save and go back to the tickets overview.
You will see the ticket is still assigned to Develop User.
Now from the tickets overview, same ticket, check the box, Bulk action - Assign Tech - Select Technician and "Bulk Assign" and the assigned to reflects correctly.