As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) FOLLOWING TAKEOFF, NR 1 ISO VLV AND ROLL SPLR INBOARD CAUTION LIGHTS ILLUMINATED. APPROPRIATE QRH ACTIONS CARRIED OUT AND THE AIRCRAFT RETURNED TO THE POINT OF DEPARTURE. NR 1 HYD QTY HAD DECREASED TO 15%. MAINTENANCE DISCOVERED THAT THE NO 1 SPOILER DUMP VALVE RETURN LINE HAD A HOLE IN IT. THE LINE WAS REPLACED AND THE AIRCRAFT WAS SUBSEQUENTLY RELEASED FOR SERVICE. (TC# 20180405001)