I'm in the process of setting up a new automatic soul urn machine. Everything was going fine, but when I climbed down from my factory tower, I noticed a massive stream of water cascading off of it. I climbed back up to find that the hopper that will add urns to a dispenser had disappeared. Figuring it was a one time glitch, I replaced it and moved on. However, approximately five minutes later it disappeared again. The only guess I have for the disappearances are the nearby(ish) hibachis that are under the kiln. However, this doesn't make sense as the hopper has bricks in between it and the fire, and the hibachis aren't even stoked yet, meaning that the bricks aren't kilns in this point in time. So, to sum it up, my hoppers are disappearing, possibly because of fire that shouldn't be there. I'm including some images to try and add reference to this.
Wait, are hoppers extra flammable or something? Those fires are not stoked at the moment, so if I remember the way fire spreads correctly, it shouldn't be able to jump through the kiln blocks to light that hopper on fire.
Fire can climb up walls, across floors and ceilings, and over small gaps. More precisely, a fire (or lava) block can turn any air block that is adjacent to a flammable block into a fire block. This can happen at a distance of up to one block downwards, one block sideways (including diagonals), and four blocks upwards of the original fire or lava source.
Your hopper is only 3 blocks above the fire!
Also bug reports => no unnecessary discussion here!
Huh, even though there are blocks in between the hopper and the fire, and the hopper is not directly on top of the fire, I guess its still spreading. Ok, I guess surrounding it should fix the problem. Unless there's something else going on here, go ahead and lock 'er up.