Its a tight motor. You can brake any motor if its not capable of turning over. A lot of times people dont know the motor is at TDC and its stuck. Yanking on the rope will rip it in half. The obvious tearing of the rope shows that too much force was used to try to get the motor unstuck. You need to heat the motor and loosen the glow-plug , loosening is not going to do much without the heating.

Im now using a pull-start d28m in my new savage-x. No problems so far as im watching what im doing. You also dont want to pull the starter but 6-8inches out , if your pulling it all the way out. Thatll do it.

Also drill based rotostarts will destroy your rotostart. As well, starting a seized motor with a rotostart will also destroy it. Always make sure the flywheel is loose, which lets you know the motor is ready to turn over.