Doe sit happen on any print from any application? Try removing the driver from the equation and go straight to CWIS and import a pdf through the Print tab.
If it does not happen to that file it is either an application setting or a driver setting. Try printing a test page from the driver properties, if it still happens it is most likely in the driver, it would be a watermark set as the default so make sure nothing is here:
If it happens only from a specific application I would need the application name.Acrobat for instance has these type of option in File > Print > Advanced > Marks and Bleeds which applies per printer.
If it happens on things like Config sheets and every job from any PC anywhere or any time it would mean the issue is Printer side, I can't find any such setting though, you would probably at that point need to call Xerox unless someone jumps in here with something I have not been able to discover.