My last boat did once, in benign weather. A case of an un-seized shackle I suspect(the suspect was missing on the end of the tether). It was seen drifting around the harbor and towed to a safe mooring.

This boat too broke loose in relatively benign weather a few years ago. It's believed something wrapped and chaffed the pendant through. The boat was repaired, and I'm sure the mooring was looked over carefully and maybe revised.

For many years we kept our boat on moorings far from home(and never had a problem).