ok pinballwizardz, I just unboxed a brand new HULK #202, and out of the box the LOKI lock was prairie dogging like crazy
Here's the fix. There are three small optos embedded in the bottom of the ramp right before the lock pin. The optos are all on one opto board which is attached to the ramp with two screws. Mine was mis-aligned in the ramp by no more than a hair causing one of the optos to mis-fire off the ramp with no ball there. Just loosen the two screws, align the opto board properly in the ramp, and boom, no more problem, and definitely not a board issue.
FWIW someone mentioned already that it was likely optos, and it certainly was in my case