Outer skin/clothes layer on invisible drowned does not render at all like other model parts

The drowned's outer skin/clothes layer which the player normally sees is not rendered at all when the drowned is invisible, and either the player is in spectator, or the drowned is on the same team as the player.

Steps to Reproduce:

1. Spawn a drowned
2. Make it invisible

   /effect give @e minecraft:invisibility infinite
   

3. Change your gamemode to spectator

Observed Behavior:

The drowned's outer skin/clothes layer will not be visible at all. Only the bottom-most part of the model will be visible translucently.

Expected Result:

The drowned's skin/clothes layer would be visible regardless of it's effect status, shared team with the player, or the player's gamemode.

Screenshots/Videos:

Invisible Drowned:

Normal Drowned: