Burning cubes in the sky - Normal?

[saharabeara]

I've recently compiled a 0.4.12 minetestserver and generated a new world with plantlife and homedecor enabled (as well as the other mods). I've only been playing for two weeks, so this is my first time compiling from source and installing a mod.

While flying around in the sky about 40 nodes up, I came across a giant burning cube in the sky. The fire eventually burned out, leaving a porous cube made of blocks with letters on the surface (which would reappear if I tried to mine them), steel and copper unmined stone, glass panes, and the occasional random object.

cube-side.png (984.63 KiB) Viewed 457 times

cube-side.png (984.63 KiB) Viewed 457 times

I found a plasma TV, red sofa, many lamps, a monitor and keyboard, a box of blueberry pies, many kinds of stairs, japanese paper doors, and even a rainbow skate board.

tv-couch-haul.png (1.18 MiB) Viewed 457 times

This isn't necessary a bad bug, but it's pretty strange!

Information about the bug:
Is the bug reproducible? Not sure, I haven't tried generating a new world, and it takes a while to find the cub.
What is your operating system? Linux - Debian Jessie
What is your version of Minetest? 0.4.12 (taken from github tag)
What game do you use? (e.g. minetest_game, MiniTest, dwarves) minetest_game: 0.4.12 (taken from github tag)
Enabled mods:
plantlife (commit 9308a5ffd5117e21ed1c078776a07eacf73d3ac2)
homedecor (commit db703e555d878b2d038213c32d4418a3eb640dc5)
(all mods enabled for this world)
(Not sure if you want the debug.txt file, or if this is an interaction with a mod.)

[Krock]

That's a known bug which is caused by the mod moretrees.
It happens when a moretrees-tree spawns in a not generated area.
My suggestion to this problem is to download and enable the mod WorldEdit to get rid of this ugly mapblock.