Depth picker for Cinematic Camera DOF doesn't work properly

I can’t consistently sample scene depth using picker for manual focus distance in Cinematic Camera, sampling on landscape mesh. Focus either doesn’t change or is placed in different area than spot I clicked with picker cursor.

This 720p 30s clip overviews my issue. Debug focus plane is enabled, bottom right shows cinematic camera view. you can see clicking around landscape mesh most of time doesn’t reposition the focus plane.

https://drive.google.com/open?id=1dekFJWLnWU1Q0oP_gQHSy935Cy6yBh9c

Additional notes:

  1. At the end, I switch on Player collision view mode, at first I thought it was landscape mesh collision issue - instead gray plane, it shows black dots arranged in grid pattern. After inspection, doesn’t seem to be issue - new, default landscape without material shows gray plane, but sampling depth is still problematic. Those black dots seem to be caused by landscape material, if I clear landscape material slot, a gray plane appears.
  2. New cinematic camera with default settings still have issue with sampling with picker
  3. Depth picking on static meshes seem to be working fine, placing focus on mesh’s pivot point. It’s just landscape mesh I can’t reliably pick depth on.
  4. Hiding foliage (small rocks) doesn’t help
    EDIT: 5. You may notice giant collisions on rocks, I’ve tried with disabling them (NoCollision preset) and switching Simple collision to Complex collision to match their shape. None of them helped.