I would check the collision settings on the StaticMeshActor being placed in the world (the one set up in the ProjectResources).
Just realised I hadn’t notified on this thread, but for a couple of updates now collision from generated meshes is supported. By applying a material to a mesh that has the ‘collision flag’ set in it’s Resource List entry, collision will be generated. If you want a ‘collision only mesh’ then you can assign a material that has no material specifed in it’s asset slot but does have the collision option enabled.