The issue here is that water colums dont update properly when over 130 blocks away from the block creating the water column. 

To recreate this issue, make a watercolumn using only 1 soulsand and then place a piston pointing into the soulsand. The piston should when powered, move the soulsand away from the water column and under then under a solid block. Then prepare a command that places a redstone block under the piston, without activating the piston. Now teleport 130 blocks away from the water column and activate the prepared command. Wait a second. Then go back and see that the water column still is present even though no block under it should create a water column.

This issue that i just explained earlier breaks some types of elevators in minecraft. I found the bug when trying to create a elevator myself.

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