After enabling the URS and if you add appointment entity in the metadata then if you create appointment then in the back end it will create the booking and display that appointment in the Schedule board.

While creating the appointment if you select the required attendees as User then it is creating the booking and displaying it in schedule board. if we are selecting the contact and customer account then it is not creating the Bookable resource booking.

Can you please consider enabling this above feature while selecting the contact and customer account in the Required attendees field while creating the appointment in URS mode.

Thanks in advance.