Unity ads rewardedVideo OnUnityAdsReady not get called in Test mode

The following function is not called

public void OnUnityAdsReady (string placementId) {
    // If the ready Placement is rewarded, activate the button:
    Debug.Log($"UnityAds ready for placementId {placementId}");
}

This is called for video ads but not for rewardedVideo in TEST Mode.

I see following message on console:

sendPlacementStateChangedEvent,
            (
        rewardedVideo,
        WAITING,
        "NO_FILL"
    )

When I look unity dashboard I see the following image (this is also interesting):
156178-screen-shot-2020-04-09-at-112117-am.png

https://forum.unity.com/threads/rewarded-videos-not-loading-on-android.1118764/#post-7201732