Having worked on heaps of roped hydraulics(not this make) I can say nearly every 1 which tripped the safety gear/governor wasn't over speeding, more that the safety gear was nuisance tripping because the safety gear pads/jaws were hitting the rails. Check your slipper guides/roller guides for wear or clearances, check your rails for loose sections. These things are a real pains when this occurs. Not saying in this instance it isn't over speeding but it could just be as above.
