Windows print server sometimes prompts for authentication

Our environment:

Print server on Windows 2008 R2 cluster

OSX 10.7.5 machines bound to Open Directory & Active Directory

OSX 10.8.5 computers bound to Active Directory

Due to networking restrictions, these machines cannot communicate directly with the printer, they must go through the print server

When manually adding the printer to each computer, users seem to be able to send print jobs without being prompted for authentication. However, after a period of time, the user's print job may be placed on hold and requires entering their credentials to send a print job. Why might this be happening?

If I add this printer to our OD Master, then attempt to map it for certain users, those users are instantly prompted to authenticate to the printer before their job will go through. On the printer that was manually added, lpoptions shows "auth-info-required=negotiate" whereas the printer deployed by OD shows "auth-info-required=username,password".

How can I configure this printer on the OD Master so that the user never has to authenticate with the printer, that their AD login credentials are automatically passed? Thanks!