We've been printing with our used C60 (~250k impressions) along with an Fiery EX Print Server for almost a year and keep on having this issue occur. When printing in color, the yellow will offset by a few cm. We do mainly B&W prints and they run great. But anytime we do prints in full color, we have this issue.
We've tried performing the Color Calibration multiple times. One time it fixed the problem, but since then, the calibration has been unsuccessful. We've removed and reinserted the yellow toner. When that didn't work, we did the same for all the toner. Tried varying the Color settings on the Fiery, but nothing has fixed the issue.
If anyone has troubleshooting steps or tips on finding a solution for this specific issue, I would greatly appreciate it.