When Minecraft is encountering any compound / list nbt tag with a depth greater than 512, it throws an exception and refuses to load the save.
This mod replaced the annoying mechanism with a harmless log warning, and let the game go ahead.
ATTENTION:
A compound / list nbt tag with a depth greater than 512 itself is abnormal, and you may check your save via NBT editor after receiving the warning in the log;
You DEFINITELY CAN add the mod to your modpack.