The Bug:

Entities' shaders are applied when beginning to spectate them in third person.

It's important to note that if you were to spectate an entity while in first person, the given entity's shader would be applied. While this is fine and is working as expected, if you were to switch into third person here and then, the shader would be removed therefore leading me to believe that there's some kind of issue here since beginning to spectate entities in third person applies the given entity's shader.

Steps to Reproduce:

1. Summon a creeper by using the command provided below.

   /summon minecraft:creeper ~ ~ ~ {NoAI:1b}

2. Switch into spectator mode and then switch into third person.
3. Spectate the creeper by left-clicking on it and then observe your surroundings
4. Take note as to whether or not entities' shaders are applied when beginning to spectate them in third person.

Observed Behavior:

Entities' shaders are applied.

Expected Behavior:

Entities' shaders would not be applied.