The flaw does exist, I can attest to it happening many times on the machine I played on in college. I personally like the game being somewhat dependent on auto-reset or a timeout and being able to use the spot during troll multiballs. But if you do want to fix it, you should understand that traps like that exist to be used and were likely preserved for that reason. The easiest way to hit that spot is to hit it off the castle gate and nudge the table right to cause the ball to fall on the troll.