Staticmesh SectionInfo map is reset when changing LODGroup

Import a staticmesh using more then one material

Change one or more section material slot index in the sections array of LOD 0

Change the LODGroup from "None" to "Deco"

RESULT

The sectionInfo map of LOD 0 will be reset in the section index order.

EXPECTED

The sectionInfoMap of LOD 0 should not be touch when changing the LODGroup, since it will be use to generate the LODs. Also for LODs we want to remove the sectionInfoMap entry not reset it to sectionIndex.