Mobs Spawn in well lit areas

Playing on a windows 10 machine on a windows 10 bedrock server. In a well lit basement, I get hostile mob spawns often. I tried carpeting most of the basement and it only helps a little. So far it's been spiders, creepers, zombies and skeletons. They never spawn in the above ground area of the house, and spawning outside seems normal.

By well lit, I have torches on the walls every 4 to 5 blocks in smaller rooms 20x20 and there are some on the interior space. Large rooms have the same 4-5 blocks torches on the walls and a torch on the floor in a 5x5 grid.