MySQL Auto_increment going 2 by 2
The prefix that was used:

SET @@auto_increment_increment=1;


Is the same as: 

SET @@SESSION.auto_increment_increment=1;


When modifying this setting, it becomes relevant only in your current session.  

To make a more permanent fix try:

SET GLOBAL auto_increment_increment=1;


Is the same as: 

SET @@GLOBAL.auto_increment_increment=1;