AddressValidationOutput class has AddressValidationProperties as its property with "x-ms-client-flatten" extension enabled. So as expected AddressValidationProperties is flattened. Case 2: ...

Unfortunately I won't be able to paste in any associated code snippets directly so I'll try to layout the scenario causing the behaviour in-question. (Using C# - EF Core 6 - Cosmos DB) There are 3 ...