World Partition streaming cells are a bit random and blocky, any ideas?

Started a new blank project in 5.2 (and tried the same setup in a 5.0 project) and this is just using individual cubes for a test, but i get the same results with my own static meshes, level instances, etc.

Nothing is parented, attached or referenced. That setup is just using the default settings from a new “open world level”

I have tried bigger and smaller cell & load sizes. Also tried a variety cube sizes too.
It usually looks like the cubes that run along the cell edges all get lumped into one larger cell size, but adding a second cell set manually didnt help any.

I feel like i am missing one of those magical unreal engine check boxes that makes everything work.

Looks like this has been a (known?) bug since 5.0 :confused: