As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS WHILE DESCENDING THROUGH 36K. CABIN ALTITUDE WARNING. CABIN ALT REMAINED BELOW MASK DEPLOYMENT THRESHOLD. QRC/QRH PROCEDURES. MAINTENANCE TROUBLESHOT IAW AMM 36-11-00, INDICATED BLEED AIR REG. REPLACED BLEED AIR REGULATOR IAW AMM 36-11-03. OPS CHECKS NORMAL.