We had the same problem on our F2 with a 13 foot head. The seals were bad, so we just replaced the seals. We had oil all over the head by this cylinder. Is there any oil on yoursIJ
There is no oil leaking from left or right cylinder,oil is leaking by internally or there is air trapped in system and I have not been able to bleed it out.
I think it could be either right cylinder or poppet in valve. Why don't you set where you want it and unhook hose for a round and see what happens. Good luck