Lapis Lazuli doesn't generate on the lower levels of the world

See screenshot from attachment xisumavoid's video (link: https://www.youtube.com/watch?v=hgVWM54A6bM)

All the ores generate at the minus y layers, with the exception of the Lapis Lazuli ore. I can't really imagine why Lapis Lazuli ore wouldn't generate in these layers, seeing as it would make Lapis Lazuli extremely hard to get in the new cave update.