As always just gotten myself into the latest Snapshot 18w19a and just started to test every thing including the water properties and noticed something... odd with the water behavior. But I do hope this has some intended usage whether or not it was left on purpose or the Mojang developers haven't gotten around to this problem yet that I have recently just found and tested.

So I noticed that when you placed down a water bucket to the side of a solid block of any type after I placed down all variations of stairs, slabs, fences (iron and cobblestone), glass panes (regular/stained), ladder, chests (regular, trapped, and ender chest), and trapdoors under the water source block the water did not flow out in any directions. I even tested it to see if it would update it when you break the solid block(s) and, incredibly, it didn't update it stood still over it. The trapdoors didn't even update when you open them and the water still stood above it not flowing outwards.

I hope this is *indeed*a bug and, rather, not a function where you can now have floating water source blocks over these objects.