The Bug:

Sculk sensors are not activated upon lighting a campfire or candle with a fire charge.

Steps to Reproduce:

• Light a campfire or a candle with a fire charge.
  →  Notice how the sculk sensor does not activate upon doing this.

Additional Information:

Quote from the 20w49a Changelog, "A vibration is anything that causes physical motion". I would definitely consider this as physical motion, as you are physically performing this task. This report closely relates to MC-207277.