Sky is darkened when in spectator mode

Steps to Reproduce:

1. Create an infinite world;
2. Turn off daylight cycle to make the issue easier to observe;
3. Observe the static sky;
4. Switch to spectator mode;
5. See how the sky color changes from a bright blue to a slightly darker shade.

Observed Results:
The top of the sky fog is darker for spectators, except when looking up.

Expected Results:
The top of the sky fog remains the same regardless of gamemode.

Screenshots/Videos attached: Yes

Notes: Changing the resolution of the game window will return the sky to its normal color, only to immediately get darker again.