On Meta Quest 2 running Horizon OS v207, GroupPresence.Set and GroupPresence.Clear calls fail with error code 2002 "OVRServiceInterface is not initialized" after the last application holding a Horizon Platform session is closed. This issue persists even after reopening the application, while other Platform APIs like Users and Entitlements continue to work. The failure is reproducible with Meta XR Platform SDK 205.0.0 in Unity 6000.5.6f1 and with older SDK versions in other applications. The issue is deterministically reproducible and can be resolved by restarting the horizon.platform.providers process or the headset.