(1) No new blocks (2) Exposed lava under water?

In a pre-existing world, there appear to be no new blocks (e.g. Deepslate and Copper Ore).

Also, I found something that I think was some kind of error - there were exposed Lava blocks underwater, not separated by Obsidian, Cobblestone, or anything else. When I mined contingent blocks, they suddenly transformed into Obsidian as I believe they were supposed to.