Despite being surrounded by obsidian, TNT can explode blocks outside of an obsidian structure.

    To reproduce this bug, place a TNT block in the air and near the ground. I used dirt blocks in the example. Then, cover all but the top with obsidian. Fly on top of the structure, and prime the TNT. Before the TNT detonates, cover the top with a block of obsidian. After the TNT explodes, several dirt blocks are destroyed.

    The expected result should not have any destroyed blocks because the obsidian should block the explosion.