Customers list is coming empty in list of MS Bookings appointments

Describe the bug

After calling Microsoft.Graph.Solutions.BookingBusinesses["id"].Appointments.GetAsync() I'm expecting to get the list of customers per appointment but the list comes empty.

To Reproduce

Steps to reproduce the behavior:

Use this example: https://learn.microsoft.com/en-us/graph/tutorials/dotnet?tabs=aad

Configure Microsoft 365 E5 instant sandbox.

Nuget Packages

<ItemGroup>
    <PackageReference Include="Azure.Identity" Version="1.8.2" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="7.0.4" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="7.0.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="7.0.0" />
    <PackageReference Include="Microsoft.Graph" Version="5.9.0" />
  </ItemGroup>

C# code

GraphServiceClient client = new GraphServiceClient(_deviceCodeCredential, settings.GraphUserScopes);
var result = client.Solutions.BookingBusinesses[bookingBusinessId].Appointments.GetAsync();

Expected behavior
I'm expecting to get the list of appointments with its customers.

like this one https://learn.microsoft.com/en-us/graph/api/bookingbusiness-list-appointments?view=graph-rest-1.0&tabs=http#response-1

Screenshots

Am I missing a configuration somewhere?

Start with the Microsoft.Graph.Solutions.BookingBusinesses[bookingBusinessId].Appointments.GetAsync() call using the listed package versions and the Microsoft Graph tutorial setup. Compare the returned appointments with the documented response and investigate the reported configuration question; done means establishing why customers are absent and identifying the relevant API or setup behavior.