My pin was experiencing the same thing a lot of right ramp rejects and I asked pat if he new how to fix this issue and he sent me this below. Before I applied this fix I could not even do a full plunge without the ball rejecting. I had to turn my flipper power down to 20 tho. It still rejects once or twice a game. Maybe I have to push the ramp down more. I would love to have it work 100 percent of the time and at full flipper power to keep the speed up. Maybe somebody could design a plastic air ball guard over that ramp flap that might fix it. Moding community please help. Let me know if this works for you or if you find anything else that will work.
Sorry to hear about your problem.
There are 2 things to check on your game.
1. Check to be sure that the left orbit inner ball guide, where it meets
the entrance/dropoff to the right ramp, is not sticking into the ramp
entrance. You should be able to feel if it is. It should be very
SLIGHTLY behind the right ramp wall.
2. Take a BLUNT tool, like the handle end of a screwdriver, and push
down on the floor of the right ramp entrance steel floor at the junction
of the left orbit drop off. You are trying to very slightly lower the
floor of the ramp entrance by bending it gently down. This ensures that
hard ramp entry shots are not hitting the edge of the junction. You only
need to bend it about 1/16" to be effective.
Good luck with your game.