Yep! So, this is the new streaming system.

What it is doing is streaming levels in/out based on where you are in relation to them. This happens for all levels that are interactive, which is why you see popping on some buildings but not others. This is a major technical change for this update - previously we loaded the entire island into memory, meaning that load times were significantly longer and the memory footprint was way, way bigger. We couldn't continue with this approach because we would not fit the story maps in console or low end PC memory.

To fix this, we need to use "LODs" for each of these buildings. Basically, if the current building is 40k tris with multiple 4k textures and materials, you can simplify that down to, say, 1000 tris, 1 material and a couple of textures. This looks like shit, but far away it doesn't matter because that detail is unnecessary. This is called having different levels of detail - LODs. However we have to manually create these - Unreal won't auto generate them for us.

Instead we'll be using InstaLOD, a new LOD creation system. We'll be able to run all of our buildings/levels etc through this and have these ready for 1.0. Unfortunately, we could not get this system into this release because it took us ~ 5-6 weeks longer to get streaming working than anticipated.