The Bug:

You can get a free elytra in Eerie Mojang Office Party Event and even retain it after the Ideas Vault Race.

Steps to Reproduce:

1. Join Eerie Mojang Office Party Event.
2. Go to the Ideas Vault.
3. Start the Cloud Race, and proceed through the race.
4. Immediately after you pass through an elytra gate, open your inventory immediately and take off the elytra. Put the elytra immediately into an inventory slot.
   • On Windows, you are able to shift-click the elytra to take it off.
5. Once you respawn in the Cloud Race, proceed through the rest of the race.
6. Once the Cloud race is finished, you can keep your elytra.

Expected Results:

You should not be able to retain the elytra after the Cloud Race. 

Observed Results:

You can retain the elytra even after the Cloud Race.

Notes:

While in the Ideas Vault, you cannot equip elytra in your inventory that you have not equipped. Once you leave the Ideas Vault, you can equip the elytra.

This was an issue yesterday in 10/December/2024 on the Eerie Mojang Party (Lobby version 2.0), when I posted the bug. This bug seems to be fixed now as of 11/December/2024 on the Eerie Mojang Party. (Lobby Version 4.0).