Everything goes grey on mobile device with fog! (Fog seems to pre-map to textures in the distance on mobile device)

Hi there. So I am having this problem on my android tablet when fog is enabled in my Unity game. Instead of maintaining a radius around the player, it seems like the fog is being pre-mapped onto large objects, so that when I move into the distance, everything goes gray.

In my case I have a few very long textured boxes (1000m long) representing a long hallway with walls. At the player's starting position, Everything looks fine:

As I move forward maybe 100-200 meters, the large objects have all faded to the grey of the fog, rather than the fog staying with the camera:

Anyone have any idea what's going on here? I have been stuck on this for a while, and it's my first issue in months that I couldn't resolve with a google search.