In earlier of versions of Minecraft, this would be ocean, since that was the default when trying to get a biome from an unloaded chunk. Presumably Forest is the new default. They could perhaps change the debug text to say unknown if there's no chunk loaded yet, but that would be more of a feature than a bugfix. As the issue is 1) in debug output, and 2) only exists for a moment until the world loads, I wouldn't expect this to change.
In earlier of versions of Minecraft, this would be ocean, since that was the default when trying to get a biome from an unloaded chunk. Presumably Forest is the new default. They could perhaps change the debug text to say unknown if there's no chunk loaded yet, but that would be more of a feature than a bugfix. As the issue is 1) in debug output, and 2) only exists for a moment until the world loads, I wouldn't expect this to change.