Lava does not properly render inner culling in spectator mode

Summary:
Lava does not display sides from the inside in spectator mode. If there is water in the chunk next to the lava, the sides will be correctly displayed from the inside.

Steps to reproduce:

1. Switch to spectator mode.

2. Find a lava lake or travel to the nether.

3. Look at the lava from the inside.

4. Place a block of water next to the lava.

5. Look at the lava from the inside.

Observed results:
The sides of lava are not visible in spectator mode except when near water.

Expected results:
The sides of lava in spectator mode are always visible from the inside.

Image: