Insert with Nullable<int> Id gives "Invalid cast" error

Im Dapper.Contrib 1.50.0, when the model is defined with an Id of nullable int and the SQL Server database is an INT IDENTITY(1,1), the result of a Dapper.Contrib INSERT is:

Invalid cast from 'System.Int32' to 'System.Nullable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]'.

Reproduction:

CREATE TABLE Car
(
    Id INT IDENTITY(1,1),
    Model VARCHAR(50)
)

public class Car
{
    public int? Id { get; private set; }
    public string Model { get; private set; }
}

var id = connection.Insert(new Car { Model = "Mazda" });

This was working in Dapper.Contrib 1.43 but is broken in Dapper.Contrib 1.50.0.

Start with the Dapper.Contrib INSERT entry point and reproduce the issue using the Car table and nullable Id model shown in the report. Trace how the SQL Server identity result is assigned, then verify that inserting the Car succeeds and its generated Id is populated without an invalid-cast error.