I recently verified this myself and found that removing the isLightOn, BlockLight, and SkyLight NBT in the mca NBT info causes Minecraft to recalculate the lighting process in the world. Source here, Reddit post.
I actually used NbtStudio to remove the three NBTs in the mca in the world, and I can confirm that the lighting did indeed improve.
One of the current problems with McaSelector is that it does not handle lighting correctly for modified mca and chunks.
So, as a feature request to McaSelector, I thought it would be easier to use if a feature was added at the location in the image below (Tools item) that would correct the lighting process for the selected mca (remove the 3 NBT items I mentioned above).
I recently verified this myself and found that removing the isLightOn, BlockLight, and SkyLight NBT in the mca NBT info causes Minecraft to recalculate the lighting process in the world. Source here, Reddit post.
I actually used NbtStudio to remove the three NBTs in the mca in the world, and I can confirm that the lighting did indeed improve.
One of the current problems with McaSelector is that it does not handle lighting correctly for modified mca and chunks.
So, as a feature request to McaSelector, I thought it would be easier to use if a feature was added at the location in the image below (Tools item) that would correct the lighting process for the selected mca (remove the 3 NBT items I mentioned above).