So i had time again to check this critical part of my application and im posting here so someone in future maybe will find this usefull :)
I have added p:remoteCommand under both buttons in code:
<p:remoteCommand name="somethingToDo" update="#{cc.attrs.update}" />
and in first button i have removed update param.
Why ? Because as error says, it could not find some dialogId ( in this example 'confirmation332m' ) and because of that update param, which was updating whole form, dialog was removed / updated.
So i moved update param from button to remote command and in
onComplete
i just call somethingToDo();
after all validation is checked.
Maybe its not best solution but for now it works ;)
PF forum link ( for future problems ): http://forum.primefaces.org/viewtopic.php?f=3&t=37851