Prusa i3 mk3 step skipping and layer shifting
Long story short: Try to replace the stock power supply.


We connected UPS between the printer supply and the wall outlet and the skips reduced to one/two per print.
We replaced the supply with random old used Mean Well SP-320 (zero care about the power panic feature, just plain 24V connected) and voilà: reference design passed.
Also few more complex designs after supply switch are still flawless, so we hope that was the problem and it's fixed now.
This Q&amp;A post is to help others to skip the major frustration and save some time.