HISMCs are currently broken in master. They always show the lowest LOD available for a mesh, so if you have a HISMC with a tree mesh set, you would always see the billboard of the tree and no matter how far you are away from it or how the settings for that specific mesh are, it never changes.
1. Unshelve CL 3263551
2. Launch QA Game Editor
3. Open Developers\jack.porter\FoliageLODWeirdness.umap (you may need to turn on the Developers Folder checkbox in the content browser)
3. Move the camera around in the editor.
4. When finished testing, please revert the shelf so the files are not locked.
White = LOD0, Red = LOD1, Blue = LOD2. Prior to the fix all foliage is always in LOD2.
Try disabling the "Use Dithered LOD Transition" flag in the LODMaterial material.
Try setting a cull distance in the foliage tool.
Compare LOD transitions to a regular staticmesh of the same SM asset "Barrel_withLOD"
Head over to the existingAnswerHub thread and let us know what's up.