I would think on your system you should have a filter on it, most likely its on the return side though. It could have a screen on the suction side in the tank. Try both first as its the easiest solution, it may have a pressure relief in the system as well,not hard to check but you’ll need a pressure gauge and a way to tap into the pressure side of the circuit. Try before the valve first then if possible after, you could have a faulty valve thats bypassing pressure to the return or could even be a bad o-ring on the piston in the cylinder.