When I moved to the new release of 1.5.6, I quickly discovered that pasteObject() is deprecated (but still appears to work) and the new command going forward is pasteObjects().
https://bugs.scribus.net/view.php?id=16332
Im wondering if the copyObject() has had any changes done too?
I cant seem to find any relevant info in the change log/history for both of these commands - other then the info provided by jghali in the bug tracker.