The Bug:
Extinguished campfires are rendered too dark when blocks are placed adjacent to them while smooth lighting is enabled.
Steps to Reproduce:
Enable smooth lighting, place down a campfire, and extinguish it.
Place blocks all around the campfire.
Take note as to whether or not extinguished campfires are rendered too dark when blocks are placed adjacent to them while smooth lighting is enabled.
Observed Behavior:
Extinguished campfires are rendered too dark.
Expected Behavior:
Extinguished campfires would not be rendered too dark.
Can confirm in 1.19.