Attempting to run this adjustment causes an error box "Confirm Standard Stock Setting" - Unable to use current standard stock setting. Select Standard Stock from Stock Library. Site techs are as stumped as I am. Error also appears to happen on some of the other FWA adjustments, but not happening currently.
After a marathon film watching session with my tech on his training films, we've found the solution. Under Automatic adjustments -> Tray settings, on the right half of the screen, about half way down, there is a button for Standard Stock. I changed it from 'not defined' to the paper I was trying to calibrate, and the issue was resolved.