Deferred Rendering, gray texture when looked up from underwater

When l looked up the world from underwater in deferred rendering, I see the grey filter ( maybe water_still_gray). 

: Although pack has correct .texture_set.json(#1) and pbr textures(#2)

(#1)--the texture_set.json which defined 

1. water_still_grey
2. water_still_grey_mer           

(#2)--

1. water_still_grey has alpha channel and it's painted over with black
2. water_still_grey_mer has alpha channel and it's painted over with black 

This issue happens to me, not just with my pack. 

platform is pc, igpu is radeon780m.