I destroyed a building by creating a selection of blocks and using a command to delete them all at once. What I expected to happen was that the light would go back to as if the torches had been removed like normal. Instead, the space that the building was once in had a dark place as if there was a shadow of the building still there. Placing torches and removing them does not resolve the issue.
Please check if that's still an issue for you in the latest 1.14.4 stable release or the latest 1.15 development snapshot.