The Bug:

Sculk sensors are not activated upon worried pandas hiding their faces.

Steps to Reproduce:

• Place a nearby sculk sensor and run the following command to summon a worried panda:

/summon minecraft:panda ~ ~ ~ {MainGene:"worried"}

• Set the weather to thunder.

/weather thunder 

• →  Notice how when the panda sits up to hide its face, 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 the panda is physically moving.