option: "allow customer to choose a specific person for the booking" option does not seem to work

Would like to discuss a problem in bookings (bookings.cloud.microsoft)

option: "allow customer to choose a specific person for the booking"

Even if i have it unclicked it still allows person to choose a person (it says optional in the booking page

but still allows person to choose one person).

Expected result would be that visitor could NOT choose a specific person if this is unchecked in settings.

I have tried changing it, and saving - but it does not effect anything. 

See pictures below - it does seem that this choice does not seem to work.