The last time I saw this issue it came up with a user’s world partitioning having some issues and they had to remake the levels, but if the assets themselves are failing, something else is likely at fault.
So technically you could build 5.1 from the source if you’ve already gotten set up for that. Here’s the page to find the release version you want, and info on how to sign up to receive access the source.
Hey there @Sean3Dmonkey! You need to sign up to be invited to the organization and then this page won’t be a 404! Here’s a link with how to do that. It will send an email to join the org, you’ll have to accept it and then you will be able to see the releases page.
It’s definitely dependent on how your game works. The “proper” way is to create data layers and hot-swap them in and out like normal level streaming, while also having the world partitioning distance streaming on top of that. You can see an example of that in the videos below, but it’s by no means the only way.