Affects Version/s: Minecraft 18w14b
Fix Version/s: None
I've included a download world, as it's a little difficult to explain. But it seems in Adventure Mode, you can't pickup water with a bucket unless you are 3 or more blocks away. It could be angle related.
This problem doesn't exist in Creative or Survival.
My world shows the lime blocks that allow you do pull water from a coordinate. Anything closer, does not allow you to.
Step 1: Create a "Redstone Ready" superflat world
Step 2: Issue these two commands on repeating command blocks.
Commands I'm using:
I don't recall this issue being present in 1.12