The biome is different between the Realms world and the world where it was downloaded, even at the same coordinates.

When I checked the previous backup, the biome was the same as that of the single world.

So I think there is no problem with the world itself, but with Realms.

There are several data packs in the world, but I don't think anything will change the biome.

I noticed this problem when trying to mark the biome boundaries.

In the realms world, the biome changed depending on the Y coordinate.