Broken reflection on surface

Good day! I have absolutely unclear situation, can anyone help?
There is a world.There is the sea, skybox, reflection capture, fog, stationary direction light and skylight.
I do project on mobile platform: androd and ios.Everywhere the sea looks as it is necessary, except iphone6 and iphone7. I get such picture:

The gray is part of sea wich have no reflection. Reflection capture and sea are bigger then skybox.

That I do wrong? Why there is no reflection on the part of the mesh?