Feet of an invisible frog do not render when viewed at a certain angle

The feet of invisible frogs will not render when viewed in spectator mode, or when the entity is on the same team as the player.

Steps to Reproduce:

1. Spawn a frog

2. Make it invisible:

   /effect give @e minecraft:invisibility infinite

3. Change gamemode to spectator

Observed Behavior:

The feet of the frog will not be visible when viewing them from below the entity.

Expected Result:

The frog's feet would be visible at all times, regardless of the entity's effects, or the gamemode the player is in.

Fix:

One possible fix is to copy the texture of the feet to the opposite side of the 2D plane. (This does cause z-fighting though and will cause the 'bottom' face of the feet to be darker, likely due to another underlying issue)