I did a search and found that this person had the same outcome as me, but the suggested fix has no effect for me.
- Modeled out Details in Zbrush.
- Fixed UV’s in Max
- Exported Max OBJ
- Store Morph Target in Zbrush
- Imported Max OBJ to Zbrush in Lowest SubD
- Morphed Target back to have the models Hi Details Restored.
- New UV Layout takes properly. (so it appears)
- GoZ or Export Lowest SubD
- Model’s UV’s EXPLODE into individual Polygons!