What screen are you using for change customer? Which screen is linked to the Change Customer button? It could be because change customer button is going to an Entity screen that has that ticket type set.
EDIT: I mean select customer not change customer.
Sorry I am going on just the knoweldge you have posted. We need to trace the behavior… it is switching ticket types when you hit the select customer button. So this means the Entity screen it is using when you press Select Customer is set for that Ticket Type.
You do not have any rules using Set Active Ticket type or Any that are set to change Ticket Type?
EDIT: From the screenshots it looks like your Select Customer is using Entity Screen other than HLJ Shop…So this means it is pulling Ticket Type from that Entity Screen.
All right, thank you very much @Kendash, the problem was with the Customer Search entity screen’s ticket type like you said. I cloned that entity screen as well and set the mappings to Admin and Cashier respectively, and the problem is gone now!