It's the latest Mac driver (3.113.0) that is causing it, remove it and use the one that comes from Apple (3.81.1) until Xerox fixes it.
What is the best way to remove the 3.113 driver?
Follow this (driver remove section)
Why would Xerox not publish a working driver?
No idea, works for most printers but utterly fails on the 51XX and 57XX models. I escalated the issue to the driver team last week and still it has not been pulled from Xerox.com
They do not, you have to use Apples update tool or just grab the files from them here