End Stone generates in Floating Islands setting

Commenting to add what I've discovered so far:

I haven't tested it with all biome options yet, but so far the bug has occurred in every single one I have chosen, which is Birch Forest, Flower Forest, Taiga, and Badlands.

So far it looks like only blocks are affected, while mob spawning is how it should be (Overworld mobs in an Overworld biome, etc.).

I can't imagine this is remotely intentional, because it makes the option to choose biomes in buffet style worlds nearly moot. Choosing the badlands biome using the caves world generation, for example, generates absolutely nothing related to badlands at all save for mineshafts with no minecart chests and overworld hostile mobs. The fact that the caves and islands generation options didn't act like this prior to the snapshot and adhered to expected results when choosing biomes, plus the fact that things are being changed by this snapshot to lay the groundwork for more customization, should be proof enough that this is a huge bug, and not remotely a feature.

The fact that the caves and floating islands generation types mimic those of both the Nether and End, respectively, doesn't mean that using those generation types must always be only the Nether and the End. Were it the case, the generation options would simply be called Nether and End, and they wouldn't bother pretending to let us choose a biome for it to generate as.

As always, please keep the comment section free from "Me too" posts, only comment if you have potentially useful information.

You get only 1 Island. It is the exact same island you get in the end on the same seed. But nothing else generates out in the void. I have tried Badlands / wooded mountains.

U can change it by changing the 

"default_block": {
{{ "Name": "minecraft:stone"}}
{{ }, }}

in the generator settings

It is caused by the world generator choosing, (sorry if there are gramar mistakes, but I don't speak english well):

When you choose a world generator, the options "Floating Islands" and "Caves" are using "minecraft:end" and "minecraft:nether" noise settings presets respectively, instead of using"minecraft:floating_islands" and "minecraft:caves". In other words; "Floating Islands" is using "minecraft:end" noise settings instead of "minecraft:floating_islands". This also happens whit the "Caves" world type, but with the "minecraft:nether" noise settings.

Here the fix I made:

At: net.minecraft.client.gui.screens.worldselection.WorldPreset, method fromBuffetSettings(WorldGenSettings, WorldPreset, Biome) and static {}

private static WorldGenSettings fromBuffetSettings(final WorldGenSettings chw, final WorldPreset dsv, final Biome bqd) {
        final BiomeSource bqg4 = new FixedBiomeSource(bqd);
        NoiseGeneratorSettings chp5;
/* START CHANGES */
        if (dsv == WorldPreset.SINGLE_BIOME_CAVES) {
            chp5 = NoiseGeneratorSettings.Preset.CAVES.settings();
        }
        else if (dsv == WorldPreset.SINGLE_BIOME_FLOATING_ISLANDS) {
            chp5 = NoiseGeneratorSettings.Preset.FLOATING_ISLANDS.settings();
        }
        else {
            chp5 = NoiseGeneratorSettings.Preset.OVERWORLD.settings();
        }
/* END CHANGES */
        return new WorldGenSettings(chw.seed(), chw.generateFeatures(), chw.generateBonusChest(), WorldGenSettings.withOverworld(chw.dimensions(), new NoiseBasedChunkGenerator(bqg4, chw.seed(), chp5)));
    }

static {
        NORMAL = new WorldPreset("default") {
            @Override
            protected ChunkGenerator generator(final long long1) {
                return new NoiseBasedChunkGenerator(new OverworldBiomeSource(long1, false, false), long1, NoiseGeneratorSettings.Preset.OVERWORLD.settings());
            }
        };
        FLAT = new WorldPreset("flat") {
            @Override
            protected ChunkGenerator generator(final long long1) {
                return new FlatLevelSource(FlatLevelGeneratorSettings.getDefault());
            }
        };
        LARGE_BIOMES = new WorldPreset("large_biomes") {
            @Override
            protected ChunkGenerator generator(final long long1) {
                return new NoiseBasedChunkGenerator(new OverworldBiomeSource(long1, false, true), long1, NoiseGeneratorSettings.Preset.OVERWORLD.settings());
            }
        };
        AMPLIFIED = new WorldPreset("amplified") {
            @Override
            protected ChunkGenerator generator(final long long1) {
                return new NoiseBasedChunkGenerator(new OverworldBiomeSource(long1, false, false), long1, NoiseGeneratorSettings.Preset.AMPLIFIED.settings());
            }
        };
        SINGLE_BIOME_SURFACE = new WorldPreset("single_biome_surface") {
            @Override
            protected ChunkGenerator generator(final long long1) {
                return new NoiseBasedChunkGenerator(new FixedBiomeSource(Biomes.OCEAN), long1, NoiseGeneratorSettings.Preset.OVERWORLD.settings());
            }
        };
/* START CHANGES */
        SINGLE_BIOME_CAVES = new WorldPreset("single_biome_caves") {
            @Override
            protected ChunkGenerator generator(final long long1) {
                return new NoiseBasedChunkGenerator(new FixedBiomeSource(Biomes.OCEAN), long1, NoiseGeneratorSettings.Preset.CAVES.settings());
            }
        };
        SINGLE_BIOME_FLOATING_ISLANDS = new WorldPreset("single_biome_floating_islands") {
            @Override
            protected ChunkGenerator generator(final long long1) {
                return new NoiseBasedChunkGenerator(new FixedBiomeSource(Biomes.OCEAN), long1, NoiseGeneratorSettings.Preset.FLOATING_ISLANDS.settings());
            }
        };
/* END CHANGES */
         DEBUG = new WorldPreset("debug_all_block_states") {
             @Override
             protected ChunkGenerator generator(final long long1) {                 return DebugLevelSource.INSTANCE;
             }
         };
         PRESETS = Lists.<WorldPreset>newArrayList(WorldPreset.NORMAL, WorldPreset.FLAT, WorldPreset.LARGE_BIOMES, WorldPreset.AMPLIFIED, WorldPreset.SINGLE_BIOME_SURFACE, WorldPreset.SINGLE_BIOME_CAVES, WorldPreset.SINGLE_BIOME_FLOATING_ISLANDS, WorldPreset.DEBUG);
         final ChunkGenerator cga3;
         final Screen screen;
         final WorldGenSettingsComponent worldGenSettingsComponent;
         final WorldGenSettings chw2;
         EDITORS = ImmutableMap.<Optional<WorldPreset>, Object>of(Optional.<WorldPreset>of(WorldPreset.FLAT), (dsp, chw) -> {
             cga3 = chw.overworld();
             new CreateFlatWorldScreen(dsp, cpz -> {
                 worldGenSettingsComponent = dsp.worldGenSettingsComponent;
                 new WorldGenSettings(chw.seed(), chw.generateFeatures(), chw.generateBonusChest(), WorldGenSettings.withOverworld(chw.dimensions(), new FlatLevelSource(cpz)));
                 worldGenSettingsComponent.updateSettings(chw2);
                 return;
             }, (cga3 instanceof FlatLevelSource) ? ((FlatLevelSource)cga3).settings() : FlatLevelGeneratorSettings.getDefault());
             return screen;
         }, Optional.<WorldPreset>of(WorldPreset.SINGLE_BIOME_SURFACE), (dsp, chw) -> new CreateBuffetWorldScreen(dsp, bqd -> dsp.worldGenSettingsComponent.updateSettings(fromBuffetSettings(chw, WorldPreset.SINGLE_BIOME_SURFACE, bqd)), parseBuffetSettings(chw)), Optional.<WorldPreset>of(WorldPreset.SINGLE_BIOME_CAVES), (dsp, chw) -> new CreateBuffetWorldScreen(dsp, bqd -> dsp.worldGenSettingsComponent.updateSettings(fromBuffetSettings(chw, WorldPreset.SINGLE_BIOME_CAVES, bqd)), parseBuffetSettings(chw)), Optional.<WorldPreset>of(WorldPreset.SINGLE_BIOME_FLOATING_ISLANDS), (dsp, chw) -> new CreateBuffetWorldScreen(dsp, bqd -> dsp.worldGenSettingsComponent.updateSettings(fromBuffetSettings(chw, WorldPreset.SINGLE_BIOME_FLOATING_ISLANDS, bqd)), parseBuffetSettings(chw)));
     }

Floating islands setting for some reason uses the "minecraft:end" setting instead of the "minecraft:floating_islands" one.

will there be floating islands with ALL biomes available?

i'd like to add that i just found stone, but it's only some of the blocks surrounding naturally-occurring lava pools. phasing through the ground showed me that this is also true for underground lava pools, however, most of the stone is End Stone.

Although it is marked as fixed, can reproduce to me in 1.16 pre3
(new world generated in pre3)

Still present in 1.16 pre-3