We're unable to obtain deepslate coal and emerald ore (preview datapack)

We're unable to obtain deepslate coal, and emerald ore while using Caves and Cliffs preview datapack, as both of said ores don't generate below y=0. Previously issue only occured for emerald ore due to its generation, but now, when deepslate blobs at y=16-0 have been removed, it is impossible to obtain any of those 2 ores in deepslate variant. I consider this a bug, because since 21w17a they're obtainable in vanilla worlds.