Appointments Location not being logged if service provider set to no preference

I have locations set up, and have different service providers for each location.

If a user chooses a location, a service and then a service provider - the booking records the location properly with the appointments admin. If they leave the service provided on 'no preference' however, the location is left blank within the admin.

This then means that when admin staff are assigning those bookings to a provider, they often assign them to a location different from what the user wanted.

What's going on there?