HLOD proxy meshes deleted when generating meshes for other sublevels

Hi,
HLOD proxy meshes generated for a sub level are sometimes being deleted when the proxy meshes for other sub levels are being generated.

Firstly, I wanted to check that everything is setup correctly:

  • We are using World Composition.
  • HLOD settings are in a blueprint and assigned to every sub level and the Persistent level. (I originally expected that we’d only have to assign it to the persistent level but this didn’t work - is this new with 4.19?)
  • The are 2 levels of HLODs. Each sub level has on average 7 - 10 clusters at LODLevel-0 and then 1 or 2 at LODLevel-1. These all build and work correctly.

The issue is that at some point the reference from the generated proxy mesh to some of the Sublevel HLOD files gets lost and then the HLOD file is marked for delete in Source control.