As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE FLIGHT CREW REPORT THAT WHILE DEPLOYING THE FLIGHT SPOILERS AT FL90, THE LT FLIGHT SPOILER DEPLOYED, THE RT FLIGHT SPOILER DID NOT DEPLOY. THE RT FLIGHT SPOILER CAUTION MESSAGE APPEARED. THE CREW THEN RETRACTED THE FLIGHT SPOILER. THE MAINTENANCE CREW REPLACED THE R/H INBOARD FLIGHT SPOILER PCU AND THE SECU NR 2.