Question No Objects Spawned by ForegroundObjectPlacementRandomizer

Hi, I must be missing something blindingly obvious.

I've setup the project according to the tutorials but the ForegroundObjectPlacementRandomizer and BackgroundObjectPlacementRandomizer don't seem to spawn any objects when I run the scenario. Looking at the scene when it's running, I can see an empty ForegroundsObjects object so the randomizer does seem to be doing something.

I've tried adding 1 or many different prefabs to the list in the randomizer but no combination or prefab works.
I've tried adjusting the depth, separation distance and placement area but no combination works.
I've added the prefabs manually to the scene to check they are working and all prefabs render correctly.
I've added a rotation randomizer tag to the assets and used a rotation randomizer, then manually added prefabs to the scene. The objects rotation randomizes correctly.

Is anyone able to help me spot my mistake please?

 

Fixed, according to this issue on github: https://github.com/Unity-Technologies/com.unity.perception/issues/427

https://unity3d.com/get-unity/download/archive