Bubble columns can float in air
They don’t launch the player but still show bubbles as if there was a water source on the soul sand.

Steps to Reproduce:

1.Place Soul Sand
2.Place water on the soul sand
3.Place a dispenser and put a bucket in it
4.Activate the dispenser
It is also possible to reproduce this bug with a magma block instead of soul sand, but magma blocks will pull the player downwards.