Mushroom biome boarder gaps?

So there seems to be a vertical gap in the biome designation.

1642 63 4510 it is a mushroom_fields biome

1642 64 4510 it is a deep_cold_ocean biome

1642 65 4510 it is a mushroom_fields biome

Is this normal? or is there some way to fix it?

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Seed: -800378642940408614

• Version: 1.18.2