Spectator Mode does not work with Oculus Integration v38

I want to develop an app using Spectator Mode in Quest2.

For now, I built the Oculus Integration sample scene, Oculus/VR/Scenes/SpectatorMode.unity, and ran it on Quest2. However, the video cast to my smartphone did not switch to Spectator Mode when I pulled the trigger on the controller.

Upon investigation, I found that the following code in UpdateSpectatorCameraStatus() in OVRSpectatorModeDomeTest.cs is not working.

if (OVRInput.GetDown(OVRInput.Button.PrimaryIndexTrigger) || OVRInput.GetDown(OVRInput.Button.SecondaryIndexTrigger))
		{
			camMode = OVRPlugin.Media.GetPlatformCameraMode();

            if (camMode == OVRPlugin.Media.PlatformCameraMode.Disabled && readyToSwitch)
			{
				OVRPlugin.Media.SetMrcFrameImageFlipped(false);
				OVRPlugin.Media.SetPlatformCameraMode(OVRPlugin.Media.PlatformCameraMode.Initialized);
				StartCoroutine(TimerCoroutine());
			}

			if (camMode == OVRPlugin.Media.PlatformCameraMode.Initialized && readyToSwitch)
			{
				OVRPlugin.Media.SetMrcFrameImageFlipped(true);
				OVRPlugin.Media.SetPlatformCameraMode(OVRPlugin.Media.PlatformCameraMode.Disabled);
				StartCoroutine(TimerCoroutine());
			}
		}

In particular, I found that OVRPlugin.Media.SetPlatformCameraMode(OVRPlugin.Media.PlatformCameraMode.Initialized); in this is not working. GetPlatformCameraMode() should be "Initialized". However, in reality, it remains "Disabled".

Is this a bug? Or am I doing something wrong?

My development environment
Unity2020.3.28f1
OculusIntegration v38.0
OVRPlugin 1.69.0

I have a whole set up for developing for Quest2 in Unity.