Microsoft.OData.Core 8.4.3: in() with nullable enum and null throws The string 'null' is not a valid enumeration type constant.

[lakshithaw99x]

After upgrading Microsoft.OData.Core from 8.4.2 to 8.4.3, queries using the in() operator on a nullable enum property fail when null is included in the value list.

This worked correctly in 8.4.2, but in 8.4.3 it throws:
Microsoft.OData.ODataException: The string 'null' is not a valid enumeration type constant.

Stack trace indicates the failure originates from enum constant validation logic inside:

MetadataBindingUtils.cs
The failure occurs specifically during:
queryOptions.Validate(validationSettings);

We assume this issue may be related to the recent flag enum support changes introduced in commit #3324

public enum Status
{
    New = 1,
    Active = 2,
    Closed = 3
}

public class Order
{
    public int Id { get; set; }

    // Nullable enum
    public Status? Status { get; set; }
}

Failing Url
GET https://localhost:5001/odata/Orders?$filter=Status in (null, 'Active')

Assemblies affected

Microsoft.OData.Core 8.4.3