Well its been investigated.
Alexander of JFBConnect (Sourcecoast) went in took one look and identified it straight away.
Nothing to do with JFBConnect.
Was this extension BS Myjspace
extensions.joomla.org/extensions/news-production/blog/14464?qh=YToxOntpOjA7czo4OiJteWpzcGFjZSI7fQ%3D%3D
With BS Myjspace there is a community builder plugin that displays the jspace tab and jspace link.
Seems the version installed wasnt creating the jspace automatically and was causing a conflict with the community builder plugin supplied by them.
Disabled it - problem went away - Community builder worked no problems at all with JFBConnect (Didnt even need to publish the CB login)
Now it seems that Bernard (publisher of BS Myjspace) has relased a new version this month so im going to test it with that and see if it clears or the problem remains.
In his latest update it can be set to automatically create a jspace page.
Im only doing this because i made such a scene and like i said if it was somethihg dumb i was doing i would have put my hands up - but its seems it was a third party community builder plugin that was the main problem.
However, i think you deserve to know the outcome in case it ever comes up again.