Player spectator head is invisible / does not render in the inventory after switching to "Fabulous!"

The bug

If you have the "Fabulous!" graphics settings on while in spectator, open the player inventory and you'll see that the head is not there.

To reproduce

1. Go in spectator mode
2. Have "Fast" or "Fancy" graphics settings on
3. Open your inventory
   → Your player head is there.
4. Have the "Fabulous!" setting one
   → Your player head is not there.

Video

Minecraft 1.16 - Singleplayer 2020-06-24 11-25-57.mp4