I have been chasing down a printing problem since I had a hotend failure (Actually it started just before the hotend failed). It looks to me like one side is too hot, it's shiny and blobby.
Now, I use a Budaschnozzle and the side that has the problem is the same side where the heater block is (with resistor) not sure if this has anything to do with it as it was the same on the old hotend that worked fine. I have lowered the overall temp down a bit (5c at a time) but still shows the same issue. While the photo is a small piece it happens on the same side on all pieces.
Bed is level, nozzle is .35mm (new as well), belts are tight.
Now, I don't know if this is relevant or not but when I changed out my hotend I used a Fluke digital thermometer that just fit down inside where the filament goes and it was within 2c of what the thermistor said it was on the computer. That being said, I had to drop my printing temperature from 235c to 215c with the new hotend or the top surface would be very rough (like sandpaper). I tried a brand new roll of filament as well as other colors with the same issue. (ALL ABS).
I am really puzzled by this particular issue.