There are regions randomly placed around the world, where water decreases by threes from the surface, like in 1.12, but others where it decreases by one from the surface, which is new. It should not be inconsistent like this
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No, I know that it is suposed to go down by one. That is how it should stay. What is a bug is that some regions still have light diffusion that goes down by 3 blocks, even in brand new worlds
Wait, newly placed water? Does that mean naturally generated water in new worlds still has 3 block diffusion? That does not seem to match what has occured, since some untouched generated water works as intended, with 1 block diffusion, while other water blocks don't.
WAI, from the 18w15a article on minecraft.net:
Water now only blocks 1 light per block, instead of 3
This only affects newly placed water - we will relight all chunks in an upcoming snapshot
The bug is already planned to be fixed in a future snapshot.