Shifted Prints, Jumps During Printing

When objects seem to have bad dimensions or if the printhead or table shows jumps during printing. Which shows like this:

Mechanical issues

Belt or the pulley is not properly fixed on motor axis. Also in some cases there can be some piece of filament between the belt and the pulley, causing shifts.

Electrical issues.

Endstop circuit is not functioning properly. Actually only for the 3.1, the opto sensors are continuously monitored. So if anything is defect, it will show on the object. When the sensor is defect, the printer thinks the sensor is continously triggered. Since the printer is not allowed to move past the endstop, it will only do movements in positive direction. 

Motor circuit is not functioning properly.

If this circuit is not functioning properly. Can be stepper driver overheating/defect, cables not properly connected to board, wire breakage, motor connector or the motor itself.