by Ken Task.
Re-check settings for backup defaults as well as the schedule for automated backups and scheduled task Never had same issue but from what it says, sounds like site lost settings?!!!
admin/settings.php?section=backupgeneralsettings
admin/tool/task/scheduledtasks.php
admin/settings.php?section=automated
Truncating all those tables, should be like running autobackups for the first time, I would think.
'SoS', Ken