Copper Torch light persists after downgrading from 25w34a to 1.21.4

Type : Bug
Affects Version/s : 25w34a → 1.21.4
Steps :

1. Place a Copper Torch in 25w34a.

2. Save & quit.

3. Open the world in 1.21.4.

4. Block is gone, but light level 14 remains at the location.

Expected : Light should be removed with the block.
Actual : Light persists invisibly.

Fix : Place and break any light block to force light recalculation.