My post seems to have vanished after I hit reply.
Thanks James for your reply, It’s certainly not the first time I’ve come across simulated physics that have to ‘warm up’ so to speak before being ready for prime time (particle systems in general tend to be that way? I’m not sure). It’s not a deal breaker because there are work arounds (camera delays if for matinee sequences, or if in game simply they would have stopped bouncing by the time the player sees them - typically).
I have noticed in the editor the cables can disappear (but are ok in game/play mode). This occurred after click drag copying a cable, and changing it to attach to another mesh. The cables then became erratic in display, based sometimes on small distance or angle changes (of the editor camera - in perspective/3D viewport). I’m only using a messy test level at the moment so it may well just need a rebuild and clean up but thought I’d put it on record in case anyone else notices.