I've noticed a strange bug that causes bubble elevator to still be present and working despite soulsand being removed by a piston. This behavior happens when the bubble elevator is around 90 blocks high and affects only the player which is using the elevator. From the perspective of any other player watching elevator operate from the ground level it would seem to operate fine.

You can watch this clip if my explanation will proove itself to be not clear enough: https://youtu.be/ldwYgT9fCS0

It seems like the client is not being informed about the "soulsand missing" event due to the distance. Anyhow, I still think that we should be able to create bubble elevators of this height or even higher.