I think that the issue you have here may be related to your other issue from this post, about canceled command.
Could you share a video of the entire calibration process, when it fails if possible ? (you can add a link to a shared Google Drive folder for example)
The first 2 things that come to my mind are :
– this can be a connection problem with either the Dynamixel bus or Stepper bus (quick deco and reco)
– this can be a mechanical problem, due to a belt which is not tensed enough, for example