Why is my custom admin menu item generating two requests when clicked?

I've implemented a simple menu provider that looks like this:

[MenuProvider]
public class CustomAdminMenuProvider : IMenuProvider
{
	public IEnumerable<MenuItem> GetMenuItems() => new List<MenuItem>
	{
		new SectionMenuItem("Custom Tools", $"{MenuPaths.Global}/cms/admin/customtools"),
		new UrlMenuItem("Log Settings", $"{MenuPaths.Global}/cms/admin/customtools/logsettings", "/customadmin/logsettings")
	};
}

Behind /customadmin/logsettings is an equally simple Razor page with a PageModel that looks like this:

public class LogSettingsModel : PageModel
{
	public LogLevel LogLevel { get; set; }
	public void OnGet()
	{
		LogLevel = SettingsHelper.LogLevel;
	}
}

The two menu items specified by the menu provider are displayed as expected, but when I click on the Log Settings menu item, the OnGet() method is called twice. What could I be doing wrong?