Unable to create Monsters from the Ice from store; stuck on loading after creating the world.

Partner Rank: 1
 
Verification builds:
Beta 1.16.64 Release
Summary:
Unable to create `Monsters from the Ice` from store; stuck on loading after creating the world.
Impact:
Major, you can't play the content resulting in refunds and 1-star reviews.
 
Effected content:
Monsters from the Ice
Monsters of the Deep
Infinity Skyblock
 
Repro Steps:
1. Buy `Monsters from the Deep` or `Monsters from the Ice` from the Store
2. Create the world
 
Observed Results:
The client is stuck on loading and never finishes.

Video: https://www.youtube.com/watch?v=zvPTgh04Vms

Expected Results:
The client loads the world.
Screenshots/Videos attached: Yes
Regression Build:
Yes, this behavior is not present on Beta 1.16.63

Notes: Confirmed on 2 windows10 devices