AR Foundation 3 And Screenspace UI Possible Bug

I've been staring at this most of the day and can't seem to figure out what I'm doing wrong. I had someone else test this and they seem to be seeing the same problem.

I have a scene that has an ARcamera (took it right from the UX sample). I believe the correct way to show a UI on top of the ar camera is to use Screen Space Overlay. So I did that for many prefabs that all have canvases. I set these to all false. Later in my script, I call a UI element that I want to show on top of the active camera and what I believe should be rendered in the screen space overlay. From there I run and build out to IOS and run through the sequence. I can see my function is being called - The UI object is not visible as an overlay.

No matter what I do when I call the object, set it to true - it will not display on the Interface. This seems like a pretty common thing to do, and everywhere I have looked it says don't use two cameras. Has anyone else experienced this?