I built the GameKitSample, and Run the app on IOS device, and there is an issue, If open the GameCenterUI from OnShowAchievements, the panel shown well, but the 'x' button is not responsible, can't close the GameCenterViewController. However, If open the dashboard by GKAccessPoint.Shared.Trigger(), the 'x' button is valid, and every looks well.
XCode : 13.4 MacOS: 12.4 Unity: 2020.3.33f1