Minecraft Lava and Barrier Bug.

If you are in Minecraft, survival or creative.
And you place a barrier block 2 blocks above the block where you are standing of. And you place a lava block on it.
If you will walk under it, it looks like you are standing in de lava, but you are not getting damage.
Demonstration: http://youtu.be/tgb-wL4GoIUMo