As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THE 10TH STAGE ISOLATION VALVE STUCK IN THE OPEN POSITION. AIRCRAFT RETURNED TO GPT AND LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE 10TH STAGE ISOLATION VALVE SWITCH BODY. CHECKS WERE MADE PER THE AIRCRAFT MAINTENANCE MANUAL AND THE AIRCRAFT RETURNED TO SERVICE.