Member Preferences: Default Member Group not saving

Hi All, I am not able to save (update) the default member group. I checked the config.php file and nothing was in there. I recently updated to EE 2.10.1.

I then added the following item found from the docs to config.php.

$config['default_member_group'] = '6';

After adding that entry, it is changed online, but I can not change (update) it using member preferences form. Config.php has 666 permissions using Linux.

Before adding the item to the config.php file, I was getting a member group that was not pending (I had this set prior to updating to 2.10.1). Where is this information saved? I assumed it was in the database, but I can not find the table.

Thanks for any info.