The Bug:
Sculk sensors are not activated upon farmland hydrating or dehydrating.
Steps to Reproduce:
Hydrate or dehydrate farmland.
→ ❌ Notice how the sculk sensor does not activate upon doing either of these things.
Additional Information:
Quote from the 20w49a Changelog, "A vibration is anything that causes physical motion". I would definitely consider this as physical motion, as these blocks are changing state.
Does MC-207286 describe your issue?