As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE UPPER DIAPHRAGM (MARKED) IN THE FWD LAV SERVICE CUT-OUT IS CORRODED. (C-CHECK) RO 5/10/2020 REMOVED CORROSION FROM THE UPPER DIAPHRAGM AT THE FWD LAV SERVICE CUT-OUT, FOUND REMAINING MATERIAL TO BE OUT OF ALLOWABLE DAMAGE LIMITS. REMOVED AND REPLACED THE UPPER DIAPHRAGM AT THE FWD LAV SERVICE CUT-OUT REF CRJ 900 SRM / DWG. COMPLIED WITH, COMPLETED FORM M-337. PRESSURE LEAK CHECK GOOD. SEE CONTINUATION CARD FOR DETAILS.