i didn't noticed this at first but when i went to an ocean to collect some kelp i saw that there it was no gravel at all also looked to warm,luke warm,cold and frozen oceans and is the same story i mean i have even found a glitched ice berge

how to reproduce it:
1:create a regular world
2:use locatebiome or find a ocean
3:dive to the ocean floor
4:done

i teste this on the older snapshots and it seems to happen ever since the new cave generation was introduced