Just checked one of my old notebooks and this one is in there.

When saving conforming items in DS4 you want the figure in the scene and the item "Fitted to" the figure, that way when you use "Figure/Prop Asset" to save it you get a wearable preset. When you don't have the figure in the scene or the item fitted to it then DS creates a subset preset, which has all of the auto conforming code missing, add in the lack of metadata and even the CMS can't act as backup and force the "fit to".

Fixing this will require some recoding of the DUF files, however they can be used as they are, right click the item in the scene tab or in the viewport and select "Fit (item name) To" and chose the figure.

I don't have anything in my notes about "prefered base" so I hope autofit doesn't start when you "Fit To".