You would be able to detect a broken Z-axis encoder while moving, I honestly think that is must be something else.
But you can monitor your encoder values in the controls card, there is a guide that should still work even if it looks a bit different:
My device is still dismantled, so I can’t give that much advice and experiences.
Let’s try to call @Marc in here, if he does not reply in the next couple of days you can try to contact the staff at contact@farm.bot for direct assistance.