What system are you on since when I tested It had worked on desktop and Vive Cosmos and uses VRC Pickup and Object sync, however the planks by the house are not pickup-able since they are example for what to look for out in the grass.

First one spawning directly out from the front door within the area by the tree, second to the right side and next ones spawning various locations as you collect more. Distance is limited to proximity of 4 to avoid pulling it from across the map but tall enough for avatars that are heads do not touch the leaves of the trees. There is an admin plank that does not de-spawn and can be used to finish the house on the top of the left mountain in the corner of the map when facing the orange side of the skybox however 2-3 monsters spawn 60-120 seconds after the 5th plank and ever one after that up to a 20 monster cap. Can confirm it still works for myself with no issues 10/23/2021 5:45 PDT