Upon the release of 1.17 I created a new world and have found that diamond ore does not spawn at all in either the stone or deepslate variants at an of the proper depths for diamond ore to spawn. I'm aware diamond ore is hard to find as is, but it doesn't seem to spawn at all and I have explored at the proper depths where it would normally spawn and haven't found any. Loot chest diamond loot remains in unaffected however.