The Bug:

Sculk sensors are activated upon crouching and casting/retrieving a fishing bobber.

Steps to Reproduce:

• Crouch and throw a snowball.
  →  The sculk sensor doesn't activate.
• Crouch and throw a trident.
  →  The sculk sensor doesn't activate.
• Crouch and cast/retrieve a fishing bobber.
  →  The sculk sensor activates.

Additional Information:

This should not be the case, as crouching whilst performing an action, prevents a vibration from being emitted.