As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED A HYDRAULIC SYSTEM LOW QUANTITY EICAS MESSAGE AFTER GEAR RETRACTION. THE CREW CONTINUED THE FLIGHT AND DURING CRUISE THE SYSTEM 1 QUANTITY DROPPED TO THE MIDDLE OF THE CAUTION RANGE ON THE MFD. THE FLIGHT THEN DIVERTED TO KCHS WITHOUT INCIDENT. MAINTENANCE FOUND THE SYSTEM 1 ACCUMULATOR WAS LOW ON PRECHARGE AND WHEN THE NITROGEN SERVICING VALVE WAS OPENED, IT EXPELLED A SMALL AMOUNT OF HYDRAULIC FLUID WAS EXPELLED. THE ACCUMULATOR WAS REPLACED WITH NO FURTHER DEFECTS NOTED.