user space usage is incorrect ( incorrect quotas ? )

Hello
I enabled quotas by this instructions
http://forum.centos-webpanel.com/centos-configuration/how-to-setup-user-quotas/

yet some account are showing more space than the original
like I have one account which via du it gives me no more than 5.9 Gb
yet in quotas page ( and user panel ) it shows 11.3Gb
how to fix this ?

after searching for the user files
I discovered that new backup (beta) module is creating a copy of the account inside tmp_bak with user owner

after deleting it .. it came back to normal quotas