Sand generating under village farms

So remember back in the 2013 days when superflat villages would randomly have sand under them for no apparent reason? Well it appears it's back in the game (though in default this time).

(I have seen this reported a couple of times, but they're all resolved as duplicates as the wrong issue. This is not caused by a pool generating underneath, as seen in the spectator mode image.)

 

You can find it in seed 8321433975529524506 at approx x=-2725, z=1925.