Is this a known GDI leak bug in .NET Framework/.NET Core/.NET 6?

Question

I have a .NET Framework Console app (4.6.2 and 4.7.2 exhibit this issue). It opens a SaveFileDialog 5 times in a row, each time waiting for the previous dialog to close.

Looking at the GDI column in TaskManager, I'm seeing the GDI object count start at 79, then go to 83, then 87, etc. It leaks 4 objects each time. This doesn't happen with an OpenFileDialog or other CommonDialogs that I've tested.

I am disposing the object, and I don't see this issue with .NET Core 3.1 (I don't see the issue in my .NET Core 3.1 app, but in the minimal example below, I do see it in both .NET Core 3.1 and in .NET 6).

The GDIView tool shows this:

Handle	Object Type	Kernel Address	Detect Counter
0xbc041a92	Region	0xffffffffffbc1a92	1
0x8410215d	Brush	0xffffffffff84215d	1
0x811024af	Brush	0xffffffffff8124af	1
0x620433b1	Region	0xffffffffff6233b1	1
0x4a103550	Brush	0xffffffffff4a3550	1
0x8e043569	Region	0xffffffffff8e3569	1
0x35103a54	Brush	0xffffffffff353a54	1
0xda013d30	DC	0xffffffffffda3d30	1
0xdc043fc6	Region	0xffffffffffdc3fc6	1

C# code:

using System;
using System.Threading;
using System.Windows.Forms;

namespace GDILeakTest
{
    internal class Program
    {
        [STAThread]
        static void Main(string[] args)
        {
            for (int i = 0; i < 5; i++)
            {
                using (var dialog = new SaveFileDialog())
                {
                    dialog.ShowDialog();    
                }
                Thread.Sleep(5000);
            }
        }
    }
}

Is this a known bug in .NET?

Update: two things that seems to address the leak (though interestingly enough, these don't help in my actual app).

1. Adding an Application.Run() to the end of the Main method
2. Removing [STAThread] and showing the dialog inside of an STA thread:

Thread t = new Thread(() =>
{
    dialog.ShowDialog();
});
t.SetApartmentState(ApartmentState.STA);
t.Start();
t.Join();