Rob and Snake, ouch.
If Im correct in the way the move works I slowed it down to 1/4 speed, the head tap launches you at the ground and you can cancel out of the animation with anymove, however d-air auto-cancels, when done too close to the ground thus, the instant cancel.
I suggest literally going though all the moves, I wonder about u-air on shorter characters.
Don't get it to work on MK because if it does work on MK we will have a HUGE INFLUX of people, or the move will get flat out banned, can't have anyone beating MK.
edit: Hmmm turns out it doesnt matter if moves land cancel, only auto-cancel, also how did you guys get it working on snake.