Using the experimental caves and cliffs gameplay in bedrock edition the terrain generation isnt as expected. All of the cave entrances from above ground are filled with water automatically at sea level even where it's not intended. Also around Y12 where deep slate would generate before the experimental mode came out, once you go deeper than deep slate would spawn after that is just ores and regular stone with no glow lichen either which makes it very bland and doesn't seem like it was as intended. I know it's experimental but thought it's worth mentioning.
Thank you for your report!
We're tracking this issue in MCPE-125379 and MCPE-125117, so this ticket is being resolved and linked as a duplicate.
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