As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 HYDRAULIC ISOLATION VALVE CAUTION LIGHT ILLUMINATED DURING FLIGHT. QTY DROPPED TO BETWEEN .5 AND 1 QUART. R & R NR 1 ENGINE DRIVEN HYD PUMP IAW WC 29-00-00R AND CASE DRAIN FILTER WAS ALSO R & R IAW MM 29-10-20. GROUND RAN ACFT. OPS AND LEAKED CHECKED GOOD.