The Bug:
Sculk sensors are not activated upon sponges soaking up water.
Steps to Reproduce:
Run the following command whilst next to water, so that you don't trigger the sculk sensor by placing a sponge manually.
/setblock ~ ~ ~ sponge→ ❌ Notice how when the sponge soaks up the water, the sculk sensor does not activate.
Additional Information:
Quote from the 20w49a Changelog, "A vibration is anything that causes physical motion". I would definitely consider this as physical motion, as water is physically being soaked up.
Can confirm