Issue migrating from WebApi OData V6 related to navigation properties in complex types

Migrating from Microsoft.AspNet.OData v5.x + Microsoft.OData.Core v6.x (ASP.NET) to Microsoft.AspNetCore.OData v7+ (ASP.NET Core) causes the following issue:

We have types like these:

public class A
{
    public string Id { get; set; }
}

public class B
{
    List<A> ListOfA { get; set; }
}

In ASP.NET OData treats type A as a complex type, but in ASP.NET Core it treats A as an entity and, as can be seen in EDM metadata, type B now has NavigationProperty instead of Property. This is a breaking change for us because this affects clients since they have to deal with a different property now and, more importantly, it does not get expanded.

Is this a known breaking change? Is it somehow possible to opt in to the old behavior?
We need to avoid breaking existing clients, can we use any extensibility points to keep the old behavior by default?

Start with the A/B model example in the issue and inspect the generated ASP.NET Core OData EDM metadata, comparing the navigation property with the prior complex-type property behavior. Done means determining whether an opt-in or extensibility point can preserve the old metadata and expansion behavior without breaking existing clients.