As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE A/C WAS IN FOR HEAVY CHECK FOUND APU EXHAUST 4TH BULKHEAD FROM AFT CRACKED. REPAIRED BULKHEAD PN 170-50120-003, IAW ETD 2021-170-002292. SEE AAR NRC 4500836-3000-0077 FOR DETAILS OF WORK PERFORMED. A/C REMAINS IN YQG FOR COMPLETION.