Check the rail mounted blocks.
This may sound like the obvious but I found that the blocks used to leed the retriever line back to the cockpit all had flats on, making it very difficult to douse the genoa. In aprticular the one nearest the cockpit had worn right through and the line was rubbing on the fixed axle. I replaced that one with a block having frictionless bearing and rebuilt the others for a huge improvement. On my H335 when I initially threaded the line back to the cockpit I missed one block that was located in the anchor locker, this block prevented the line from caffing on the sharp end of a screw (I bought my boat on the hard so didn't know that block was there). Might be something to check.