As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#2 ENGINE SLOW TO COME OUT OF FEATHER. REMOVED FROM SERVICE. HAD CREW ENGINES #1 & #2. PERFORMED FUNCTIONAL TEST OF PROP TIME TO UNFEATHER IAW Q400 AMM TASK 61-20-00-720-802. ENGINE #1 WITHIN LIMIT. ENGINE #2 OUT OF LIMIT TAKING APPROX 45 SECONDS. FAILING FUNCTIONAL TEST. REPLACEMENT OF THE #2 PROP PISTON SEALS. ALL OPS CHECKS GOOD. TIME TO UNFEATHER NOW WITHIN LIMITS. AIRCRAFT RETURNED TO SERVICE.