I actually kicked it up sligbtly at the rail side vs level. Your's looks worse for it though.
Softening the ramp mount to absorb some vibration? (foam/tape) or at the vibrator? Adjusting power slightly might help too.
When I didn't have correct culverts, I padded the ramp top at the pickup spot with clear tape to gain 1/32" or so at the pipe edges. (not why, but it helped too)
I honestly think they left a little "weak" design in place sometimes without much worry, because for kids, problems can be play value. Kids love to fidget too, and little issues teach physics skills without really trying hard to do so.