The ARKit game template runs perfectly out of the box. White spheres cones and cylinders drop out of the sky onto a detected flat surface leaving a contact shadow.
However!
As soon as even a minor change is made. For example changing the list of available static meshes to place, changing the static mesh material, spawning a static mesh other than BP_Placeable etc. etc. basically most changes to the original blueprints cause the App to crash when run on my iPhone 6s.