Yes, I understand better now. I have turned off auto weld in the roots of my attached child actors and it seemingly makes no difference. I need to do more tests but you are correct that the plugin is not involved here and what I am seeing is a peculiarity with child actor components and physics objects. I know there have been problems with child actors and realise that workarounds are needed for some things. Another one may be needed for or it may be a genuine bug.
Of course having written I will immediately find it’s all my fault… I appreciate your expert help, I’m pretty certain the auto-weld behaviour is at fault here once you brought it up.
I appreciate that adding child actors as components can be a sledgehammer to crack a nut but we have a great feature that means I must get them working in case.
EDIT: Attached Child Actors set to simulate work perfectly with the gripped object but are free to move independently of it. Auto weld setting has no effect. I may experiment with setting simulate and/or force welding the child actors on Construction or On Play as attempted workarounds.