Servo-controlled motion can reach a commanded number while the mechanical component is in the wrong physical position. Incorrect homing, encoder coupling slip, lost counts, backlash, loose drives, soft-limit changes, or thermal growth can shift plugs, platens, clamps, and transfers.
Reference position, actual position feedback, physical measurement, and repeatability should be checked through the operating stroke. A fault that resets after homing points toward reference or feedback; a load-dependent shift points toward coupling, stiffness, or mechanical slip.
Homing hardware, encoder mounting, drive parameters, limits, and mechanical connections must be corrected by qualified personnel. Heater or timing compensation should not be built around a moving coordinate system. Position verification should be part of tool-change and maintenance procedures.