As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IN CRUISE FLIGHT, THE FLIGHT CREW RECEIVED AN AMBER HYD VOLUME A LOW CAS MSG. THE FLIGHT CREW ELECTED TO RETURN & AN EMER WAS DECLARED FOR PRECAUTIONARY MEASURES. MX CREWS FOUND THE LT A SYS HYD PRESS TRANSDUCER O RING TO BE LEAKING. THE O RING WAS REPLACED & THE LT ENG DRIVEN HYD PUMP WAS ALSO REPLACED DUE TO BEING OPERATED DRY. OPERATIONAL & LEAK CHECKS WERE NORMAL. THE ACFT WAS RETURNED TO SERVICE WITH NO FURTHER ISSUES.