Got another network printing question for y'all.

All of my printers have been successfully configured and are operating nicely on my new NetWare 4.11 servers under NDS. The only problem is that sometimes a random printer or two will unconfigure itself for NDS and will, of course, stop printing. When I check NWadmin everything looks ok, but HP Web JetAdmin confirms that the printers are unconfigured for NDS and I have to set them back up on their queues again. Can someone tell me why this is happening and how to stop it?

Thanks!