As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOTH VOR'S OFF CENTER LINE 2-5 MILES. ATC RECORDS 20 DEGREES OFF WHILE BOTH VOR'S SHOW CENTERED IN AIRCRAFT. HARRISBURG SHOWS CENTERLINE AT V377 WHILE ATC SHOWS 2 MILES OFF. AIRCRAFT WAS FLYING 2 MILES OFF COURSE WHEN NAVIGATING WITH BOTH VOR'S. AIRCRAFT RETURNED TO IAD IS AWAITING MAINTENANCE.