The Joomla 3.4.7 update changed the session handler (mentioned in this LinkedIn posting )
The job scheduler fails. Looking at the error log here /administrator/components/com_civicrm/civicrm/error_log shows errors like the following:
[24-Dec-2015 05:24:01 America/Chicago] PHP Fatal error: Call to a member function get() on a non-object in /home//public_html/libraries/joomla/session/session.php on line 448
I also mentioned this in this other stackexchange posting but I think that posting is considered answered.
Do I need to file a bug report anywhere else?