As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AMBER "COMBINED HYD QUANTITY" CAS MESSAGE AT FL410. THE COMBINED HYD SYS QTY INDICATION (EICAS) READS ZERO. THE FUSELAGE COMBINED SYS GAUGE ALSO READS ZERO. NO HYD FLUID FOUND IN EQUIPMENT BAY OR OUTSIDE FUSELAGE. R & R THE COMBINED HYD RESEVOIR & FOUND SATISFACTORY.