As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DEPARTURE AT ROTATION HAD A STATUS MSG L EMERG INST XFER BUS MSG AT AROUND 4000FT. MTC DID AN INSTRUMENT BUS VOLTAGE SENSING UNIT TEST FOR THE CAPT IBVSU NO DEFECTS NOTED AT THIS STATION IAW B767 AMM REF: 24-51-04 ITEM F AIRCRAFT REMAINS NO ETOPS. A/C RETURNED TO SERVICE.