The bogged's outer skull and moss on their body which the player normally sees is not rendered at all when the bogged is invisible, and either the player is in spectator, or the bogged is on the same team as the player.

Steps to Reproduce:

1. Spawn a bogged
2. Make it invisible

   /effect give @n[type=bogged] minecraft:invisibility infinite
   

3. Change your gamemode to spectator

Observed Behavior:

The bogged's outer skull and moss will not be visible at all, the player will only see the inner mushroom part.

Expected Result:

The bogged's skull and moss would be visible regardless of it's invisibility status, shared team with the player, or the player's gamemode.

Screenshots/Videos:

Invisible bogged:

Normal bogged:

Notes:

Will add related issues later