Custom dimension option "disable_mob_generation" does not appear to work

Setting the custom dimension option "disable_mob_generation" to false in a custom dimension does not appear to stop mobs from spawning, both passive and hostiles still spawn.

This option should be respected, better yet, there should be options for different groups of mobs or the ability to disable on a per mob basis. Cod and other such mobs cause a lot of lag but don't provide much additional gameplay, it would be good to be able to disable them in certain dimensions.

.../custom/void.json

{
    "generator": {
    "settings": {
        "disable_mob_generation": true,
        "structures": {
            "structures": {}
        },
        "layers": [{
            "height": 1,
            "block": "minecraft:air"
        }],
        "biome": "minecraft:the_void"
        },
        "type": "minecraft:flat"
    },
    "type": "minecraft:overworld"
}