Jobs printed. Log owner as workstation instead of username

Hi,

I have a Server 2008 R2 print server, serving a mixture of clients 7,XP (32&64).  We have Papercut (print logging) software installed on the server.

We are seeing intermittent jobs on Print Queues logged as workstation name instead of username, it is on random jobs i.e. Word, PDF, Internet Explorer and random clients.  Unable to find a common link as to why it happens

See Papercut kb - www.papercut.com/kb/Main/JobsOwnedByComputer

We have denied computers object as well as individual workstations on the Print Queue but it still allows computers to print.  It seems like a bug in Windows that this is still allowed to occur.

Any ideas?

Cheers

Ross