Affects Version/s: Minecraft 1.13-pre1
Fix Version/s: None
When I tried the new 1.13-pre1 version of Minecraft, I found a bug.
When you try to look trough the empty part of a water selected block, like an halfslab that is placed underwater, the hitbox of the halfslab is selected and not the block behind it. I think it has something to do with the water being inside the halfslab. It also happens with other blocks that can hold water, like stairs, walls, fences, etc...
I hope this gives enough information.