Scale objects above 3k became black with enabled vertex fog (mobile es3.1)

What I have done:

  1. created default ue4 mobile project
  2. open default any scene
  3. add default sphere to level and set unlit (or lit no matter) material with two sided
  4. scale sphere to 3k or above
  5. disable settings->rendering->disable vertex foggin on mobile devices
    What we can see on mobile:
  6. Development build: we can see the sphere…looks correct
  7. shipping build: only dark instead of sphere. (I tried to change scale at runtime and I have see like sphere started became black between 2k to 3k scale (looks like lerp) and disappear above 3k)

The result is: I can’t use any sky on mobile

Any ideas?