Duplicated shot won't allow me to change the camera path

I have a shot with a camera following a spline path. If I duplicate the shot in the Content Browser and try to assign the camera in the duplicated shot to a different spline path, instead of following the new path it appears to just sit at the world origin.
If I then delete the camera and create a new one I cannot add a Path track.
So I am having to recreate an almost identical shot each time because the camera seems to get messed up when the shot is duplicated. A little annoying.
Any one have any ideas on a fix?

OK. Found a fix - delete the Path track within the camera track and then add the Path track in again pointing at the new Path. Appears to fix whatever was broken:)