HLODs appear dark/near black when built for very large geometry with Virtual Textures enabled

Building HLODs for a very large landscape with Virtual Textures enabled results in the built HLODs being very dark for the most part. Building the same large landscape's HLODs with Virtual Textures disabled will fix the issue. The editor can then be restarted to re-enabled Virtual Textures and the built HLODs will remain correct.

The issue is present regardless of texture samplers used, material instance overrides, or materials used at all (all things that have previously interacted in strange ways with HLODs in the past). HLOD layer settings and World Partition Runtime Hash class also both have no effect on changing this behaviour.

This seems to purely be an interaction with large landscapes (or other large geometry potentially) having their HLODs build while Virtual Textures are enabled.

• Create a new 5.4 project
• Import a very large landscape (repro project uses 16k x 16k)
• Enabled Virtual Textures in the project settings
• Build HLODs
• Observe the HLODs are marjority dark/near black with one or two spots that are properly textured
• Disabled Virtual Textures and repeat
• Observe that the HLODs are properly textured now