Just want to also confirm this bug for a separate scene. Having the instancedStaticMesh as a child of a mesh, crashes my Unreal on play. Using a scene as root didnt fix, but moving the instancedStaticMesh to a child of the root did fix it (so its parent was no longer a staticMesh). I was building my instances directly in component tab and contained no BP code. Unreal 4.6.1.