Cool, never used that before…
I guess this is a problem with the order that things are calculated (first Collision and then Rigid Body). This hangs together with the Dependency Graph and will probably be fixed when we get ‘Everything Nodes’.
We can get this to work by duplicating the Plane, Removing the Collision from the original Plane and removing the Rigid Body from the duplicate. Parent the duplicate to the original and then it works.