I was watching a video but in my case it was headgear that had the same problem as you. make sure you weight paint, drag model into Skeleton add armature modifier and add to Root. then when exporting uncheck "add leaf bones" and check "custom property's" once its in the workbench you want to click on your bit of clothing and go to import settings. check "Export skinning" and then click "reimport resource" you should be aiming for a max of 163 bones anymore and it seems to break like in the video you showed.
