Players' capes illogically point upward when flying with non-elytra items

The Bug:

Players' capes illogically point upward when flying with non-elytra items.

Steps to Reproduce:

1. Ensure that you have a cape enabled.
2. Give yourself a diamond with the appropriate components by using the command provided below.

   /give @s minecraft:diamond[minecraft:glider={},minecraft:equippable={slot:'chest'}]

3. Equip the diamond into the chest slot and begin flying.
4. Enter third person and look at the angle of your cape.

Observed Behavior:

Players' capes illogically point upward when flying with non-elytra items.

Expected Behavior:

Players' capes would not point upward when flying with non-elytra items.