As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 3718 (RIC TO DTW) CREW RECEIVED TOILET SMOKE MESSAGE ON FINAL WITH NO SMOKE OR FUMES OBSERVED. FOUND SWITCH FOR TEST STUCK IN, UNSTUCK SWITCH. OPS CHECKS GOOD. REPEATED OPS CHECK (10 CYCLES) COULD NOT DUPLICATE DISCREPANCY NOR GENERATE ANY OTHER. OPS CHECK IAW AMM 26-16-01. OPC GOOD AT THIS TIME, AIRCRAFT OK FOR SERVICE.