SqlConnection doesn't get closed after using statement

Question

I have problem with SqlConnection in ADO.Net. I expect that after end of using{}, the connection will be closed automatically. Why isn't it?

public void Connect()
{
    using (var cnn = new SqlConnection(ConnectionString))
    {
        Console.WriteLine("got connection");
        Console.WriteLine("retrieving a scalar value");
            
        Console.WriteLine(cnn.State);
        int allRows;

        string sql = "SELECT COUNT(*) FROM [AdventureWorks2019].[Person].[ContactType]";

        using (SqlCommand cmd = new SqlCommand(sql, cnn))
        {
            cnn.Open();
            Console.WriteLine(cnn.State);
            allRows = (int)cmd.ExecuteNonQuery();
        }

        Console.WriteLine(cnn.State);
    }
}

I get output:

got connection
retrieving a scalar value
Closed
Open
Open

I expected:

got connection
retrieving a scalar value
Closed
Open
Closed

I already use POOLING=FALSE; in connection string, but didn't change anything