World Chunks Disappearing in Marketplace Map (City Living 2)

Summary = World Chunks disappearing when reopening world after update 1.20.1 
Repro Steps: Download the mcworld attached and import it into Minecraft
Go to the Marketplace and Download City Living 2 (This will make sure the world has the missing Resourcepack and Behaviourpack)
Load the world you imported world (Make sure the Resourcepack and Behaviourpack are not missing)
Observed Results: The world chunks are gone, apart from some that are left. Able to engage with Entities
Expected Results: World chunks to be present and loaded correctly
Screenshots/Videos attached: Yes