The Bug:

Sculk sensors are occasionally not activated upon a villager leaving a bed.

Steps to Reproduce:

• Interact with the bed that a villager in sleeping in. (Right-Click by Default).
  →  Notice how occasionally, when the villager leaves the bed, the sculk sensor does not activate.

Additional Information:

I've attached a video which demonstrates this issue. Here you can see that occasionally, when a villager leaves a bed, sculk sensors sometimes don't activate.