Put the summary of the bug you're having here

What I expected to happen was...:
Its bassically patches of Of Black spots with No Light at all placing blocks would not update it and had its light level 0 Mobs spawn there even in the day and anytime

What actually happened was...:
I was walking in my hardcore world  In early day after obtaining my objective from night armour is low in defense i was confident cause its day when i stepped on it before i knew it my armour broke and died there was a bigilion mobs i got angry and decided to look for the bug in a creative world and report it and i discoved alot of things  about it its light level it 0 it appears randlomly and mobs can spawn even mid day and can pack lots of mobs or a little amout like in the screenshots reloading the world makes it disapear tho but its still annoying not gonna lie

6164880674085669734 Here is the seed incase and the coords are in the images

Steps to Reproduce:
1. There is no way to create the bug it just happens randomly