Small structures are deformed after switching to Duet Wifi I just switched to the Duet Wifi board (used MKS Gen L 1.0 before) and now small structures look terrible. From my observations the hot end moves correctly, but almost no filament gets extruded. On the other hand larger structures look very good. With the MKS board the exact same G-code worked fine.
After that I gradually disabled many features like coasting, wiping and even retractions altogether, the quality only improved by a tiny margin.

Example print (the two towers should be cylinders):


Additional information:


Printer: JGAurora A5
Material: PETG
Slicer: Simplify3D


More info (edit):


Hot end temperature: 225&nbsp;°C (for the affected layers)
Bed temperature: 60&nbsp;°C (I corrected the thermistor data, it's equivalent to 70-75&nbsp;°C on other JGAurora A5 printers)
Nozzle diameter: 0.4&nbsp;mm
Part cooling fan: 100% (improved cooler duct by Da Hai Zhu)
Print speed: 50&nbsp;mm/s (50% for outline)
The cylinder is printed hollow because of my infill settings
Lubricant is fresh, belts are tightened, so there should be no mechanical issues
The OP found the solution and shared this in comments but has not written a proper answer. The OP found:


  To complete this, the issue was related to the part cooling fan not spinning correctly. After replacing it the problem was gone.