WindowStartupLocation = WindowStartupLocation.CenterOwner does not work on multiple displays

[digitaldias]

I have two screens, and if I move my app to the secondary screen and run this:

    private async Task<bool> GetUserConfirmation(string title, string message)
    {
        return await Dispatcher.UIThread.InvokeAsync(async () =>
        {
            var dialog = MessageBoxManager.GetMessageBoxStandard(new MessageBoxStandardParams
            {
                ButtonDefinitions = MsBox.Avalonia.Enums.ButtonEnum.YesNo,
                ContentTitle = title,
                ContentMessage = message,
                Icon = MsBox.Avalonia.Enums.Icon.Question,
                WindowStartupLocation = WindowStartupLocation.CenterOwner,
                EscDefaultButton = MsBox.Avalonia.Enums.ClickEnum.Ok,
            });

            var buttonPressed = await dialog.ShowWindowDialogAsync(_parentWindow);
            return buttonPressed == MsBox.Avalonia.Enums.ButtonResult.Yes;
        });
    }

The dialog will appear between my two displays. I can't get a window for it either, so I can't fix it unless you have a good way to grab the Window component of this dialog by a nice cast.

Edit:
I realize that I may be doing something wrong, too, but It'd be nice to know.
Here is a picture of how it looks on my second display. It is fine and centered on my primary display.