First, remember that there is an option on the schedule screen to show the job colors as the color for the vehicle they are assigned to instead of the zone color. Right-click on the schedule, go to Color By and be sure Zone is selected and not Vehicle.
If you do have it set to color by Zone and not vehicle, then it must be that the zone is not correctly assigned to the Site address for the order. Open the order that doesn't appear to be showing the right color, right-click on it, choose Site > Edit Site, and there be sure the correct Zone description is entered. Then resave the order, and reload the schedule, and it should now show the correct color for the job.
If you still have a problem, then check your Zone list (Misc / Setup > Zones) and be sure you have the correct color setup there for the zone description in question.
keywords: color, colors, schedule colors, zone color, zone colors, job color, job colors