Quoted from Sinestro:
The switch behind Stay-Putt isn't a code issue. It's a design flaw because fast balls sent up the Ecto Lane lift off the ground when they go around the corner and the switch isn't depressed enough. Likewise, a softer plunge up the Ecto Lane seems to almost alway work.
I tried bending my switch to make it more sensitive, but the switch would close when I screwed it back in. I bent it back to get it working again, but same % of failure.
Stern should have put another Opto in there, or a physically different switch that could be closed when a fast ball is shot through the Ecto Lane.
I also have this issue,and am trying to find an easy solution. I hate not getting credit for that shot,and often post pass to backhand it. Id say it only registers 50 percent of the hard shots from right flipper. Pretty frustrating