1. Remove SMR info, by selecting the child elements you want to un-rig and pressing the Remove SMR info button (X) in SMR Helpers panel (or Smart Magnet Rig panel).
2. Depending on what the actual issue is, you may need to also remove the Magnet Targets inside the parent element. (Never duplicate (copy/paste) MTs that already contain SMR info.)
3. Rig the element again, using the FreeStyle Rigging tool.
If you experience more issues, my advice is to select all elements, remove SMR info by pressing the (X) button, then delete the EDAPT Objects folder from the Library (it contains the MTs and CMs) and start over.
More information can be found here: https://flash-powertools.com/smart-magnet-rigging-process/#sr05
Also, it will be a good idea to download one of the sample rigs and make sure that the tools are working well, before attempting to rig your own characters.
Hope this helps!