While printing a circular scale knob, I noticed that the scale quality is worse on the back of the part. Regardless of the filament I use, the scale lines on the back are blurry. The printer has been serviced, the belts are tight and overall it is in good condition. The only thing I haven’t tried yet is changing to a different nozzle. Any suggestions?
Might be related to seam positioning, as fine details near seams tend to look worse. I also notice a lot of ghosting which indicates that you may want to run a vibration compensation calibration (probably won’t do much) or turn down the accelerations to something around 1k. Those are my suggestions, but I probably am missing something someone else knows 
For the quality to be asymmetric like that, and be consistent across filament types and temperatures, means there has to be something asymmetric in the mechanics, it’s not heating-related.
The position system wouldn’t do it repeatably if, for example, a belt or idler was loose. Defect pattern would be random.
So whatever is asymmetric is “fixed” and that leaves the nozzle as the most likely culprit. Bent, or worn out maybe.
IMO nozzle.