This is an old CNC lathe machine with stepper motor and drivers, move the carriage with MPG, the CNC lathe controller’s screen showing the numbers still changing after stop the MPG, and the axes carriage is still moving. But if use the rapid moving key on the CNC lathe controller, no any problem.

Measure the machine double interval with dial indicator, the error is within the tolerance.

Then it should be mechanical problem, uninstall the ball screw and found all the bearings are damage, change the ball screw and bearings, and clean the machine, problem solved