I fond this bug while building a map.
if you use x y z with brackets like @e[x=?,y=?,z=?,dx=?,dy=?,dz=?] it wil detect higher than this coordinates and it will be stretched out to 3 time's its size on the Z axis.
I cannot upload my videos because they are too large.
I have zipped them so that you can still use them: http://www.mediafire.com/file/wx3enlt0gwd2spu/Video_Minecraft_Bug.zip/file
Sorry for my english.