[TaylorAlexander]

So the term "losing a step" is used on stepper motors, which can be mechanically overpowered to lose positioning. Encoders however will typically always measure the position accurately even if you overcome motor torque and disturb the motor. So in that sense "lose a step" simply does not apply here. Steppers can lose positioning by being pushed beyond their holding torque, while brushless servos will not lose their positioning in the same situation.

[jacquesm]

The fix for that was to bolt an encoder onto the stepper just as with the servo, but in practice these systems do not work very well.