People
I have discovered a way to not have the problem.
For some reason, the lines above of wp-admin\includes\admin.php where deleted on new version:
if ( !defined( 'AUTOSAVE_INTERVAL' ) )
define( 'AUTOSAVE_INTERVAL', 60 );
I just put it again (and in my case I changed the parameter value to 120s) and now it is working fine.