I don't have the issue printing on my Windows 10 PC, are you possibly using the v4 or MS class driver?
The 2 I have are v3 drivers from Xerox and can be seen above. If you have the v4 class drivers (Windows 10 installs them during the update process, you may be able to fix it with a quick download and install of the Xerox driver (I suggest the PS Global driver)
If it only happens in Edge browser you would need to file that with Microsoft not Xerox.
Only thing you can do in the Xerox side is modify some driver settings and hope.
These highlighted ones may help, but are not guaranteed in any way.
When Edge browser in Windows 10: The first print job of the day is grayscale, then all subsequent jobs are color. If some hours pass without printing, the following print job will come out in grayscale again.
What is causing these jobs to come out in grayscale?
Thanks for any help.