The FAA reported: "AIRCRAFT EXPERIENCED A DUTCH ROLL, REGAINED CONTROL AND POST FLIGHT INSPECTION REVEALED DAMAGE TO THE STANDBY PCU, OAKLAND, CA." and stated the aircraft sustained substantial damage, the occurrence was rated an accident.
The PCU in this context is the part that moves the rudder. PCU issues were common on the 737 in the 90s[0] although that's... probably?... not relevant here.
