When an enderman holds a block, the block is rendered darker than it should be.
Run the following command:
/summon minecraft:enderman ~ ~ ~ {carriedBlockState:{Name:"minecraft:stone"}}
→ The stone held by the endermen is rendered too dark
MC-161390 Mobs holding items will make that item lighter or darker
MC-161274 Items are rendered bright in dark areas when holding them in the hand