UE 5 + Groom/Hair is not working properly

Development Rendering
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14

UE 5.5 has a new cvar that greatly improves skylight occlusion:

r.HairStrands.SkyLighting.ScreenTraceOcclusion 1 combined with
r.HairStrands.SkyLighting.IntegrationType 1

Hair_Sky_Occl_5.4
Hair_Sky_Occl_5.41280×720 799 KB

Hair_Sky_Occl_5.5
Hair_Sky_Occl_5.51280×720 761 KB