Probably a job attempted via USB and it failed, then the person doing it removed the USB and walked away with the job hopelessly broken in the spooler, now it keeps attempting to print it.
FujiXerox printers are not really supported by Xerox, but if this is the case, typically unplugging as much as possible (Network cables) and rebooting 3 times in a row should clear the spooler and cache (Do nothing on the copier between reboots)
That or you have a new bug/glitch/issue relating to a security suite scanning the LAN for issues/security holes (Occasionally the scans will end up being printed by a printer simply because it comes through a print port/protocol)
Our Unit has started spitting out hundreds of pages with jobs we are not initiating? The menu display, is saying the job is generated by USB - but there is no USB installed in the printer - and when it starts spitting out pages, they have random characters 7 or less in number.