Hmm, honestly, I have no idea what to do in this situation, parts and accessories are setted up fine, probably roblox is just buggy. Maybe you can try to spawn dummy outfit and exactly dress it up as your character
I may have found the fix, basically create a dummy from the rig builder and edit it instead of using a player’s rig or just delete every single attachment in the rig’s torso (or specifically the ones who are causing the problem)
I’m not at home right now but I’ll try this solution as soon as possible, I’m using the rig editor though so I’m not sure if this solution may work (also, attachments are what attach accessories to its respective character parts). I created a new topic about it: Body attachments aren't being detected, HeadWelds forcefully being created