deadmau5's ears do not render translucent when invisible

The bug

When deadmau5 is invisible and their model is rendered as translucent, the ears disappears completely.

How to reproduce

Setup

1. Locate your versions folder
2. Make a copy of the latest version folder that you'd like to test the issue in and append _custom to the copied name, resulting in for example 20w45a_custom or 1.16.4_custom
3. Delete the .jar file inside the folder
4. Append _custom to the name of the .json file
5. Open the .json file in a text editor
6. Find ${auth_player_name} and replace that with deadmau5 (this should be on the first line)
7. Find ${auth_uuid} and replace that with 1e18d5ff643d45c8b50943b8461d8614
8. Finally, locate the version id (for example 1.16.4) within the file (should only be present once) and append _custom to it
9. Create a new installation in the Minecraft Launcher and set its version to your custom installation
10. Launch the installation

Reproduction

1. Create a team by running the command:

   /team add deadmau5

2. Join the team:

   /team join deadmau5

3. Apply the invisibility effect to yourself:

   /effect give deadmau5 minecraft:invisibility 1000000

4. Enter third person view
    The ears are not rendered translucent

Screenshot

I do not own the username "deadmau5" neither do I know the person owning it personally. The attached screenshots were created by using "deadmau5" as username. The screenshots were taken for testing purposes only.