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.