No, unfortunately I didn’t not resolve it. Even if I delete sky and some of the meshes (except the one I stand on), I can never reach 60 fps. That time when I saw 60 fps on the screenshot was a fluke - I can’t get it anymore. And I didn’t even change a thing! 
What fps values and render time values did you get during your tests ?
What’s puzzling is what are 17 ms spent on in an “empty” scene? There are several people who are unable to achieve 60 fps in an empty scene and they also wonder why 17 ms spent on whatever UE4 is doing, where is nothing obvious to do (nothing to render besides a box, no game logic, etc.)
I’ll do some more tests over the weekend and will provide another test build.