Demographics_User->save() kept trying to insert a new record instead of updating the old one.
I tracked the problem down to Demographics_User->_base_id not being set if the class was loaded via Demographics->getList(). _extend_id & _new_user also turned out to be not set.
This patch fixes that.
Demographics.php patch
Logged In: YES
user_id=400519
Originator: NO
Thank you. It is now fixed in SVN.