As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STARTER CUTOUT EICAS MESSAGE 1.5 HRS AFTER TAKEOFF. ON RETURN TO DEPARTURE MESSAGE WENT AWAY BUT GOT BLEED 4. CYCLING ON/OFF WITH 10-15 PSI DUCT PRESSURES ON ISOLATED SIDE. FOUND ENGINE 4 PRSOV PARTLY OPEN ON ENGINE SHUTDOWN CAUSING BACK PRESSURE AND STARTER CUT OUT MESSAGE. PRSOV DEACTIVATED ACCORDING TO MEL 36-11-01.