hi @maxbrown
Look at this in ue5main 5.5 and you will see the commit
Mark LightmapType in PrimitiveComponent as deprecated for 5.5, it's …
…now behind accessors so that we can control this behavior across all actors depending on settings (actual code doing this to come in a subsequent CL)
Comparing to April when 5.4/ue5main was working in my repo
EPIC-GPULightmass55Valid
to ue5main now there are loads of changes, possibly causing problems you are seeing