As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION TYPE:N/A, MASTER FIRE WARNING LIGHT ILLUMINATED AND FIRE BELL SOUNDED MOMENTARILY ON 3 SEPARATE OCCASIONS IN FLIGHT. NO SOURCE OR OTHER SUPPORT INDICATIONS OBSERVED. RESEATED ALL FIRE WARN CARDS, OPS CK ENGINE, CARGO FIRE, SMOKE WARNING SYS AND OPS CK GOOD.