Dark Oak spawning incorrectly.

If there is some kind of river or ocean around a roofed forest you might find a dark oak tree that spawned (naturally) over sand or gravel. In some cases they spawn in the air. Fix it please .

Seed: -943123844013429995
Picture 1 Coords: x: -1565 y:62 z:1477
Picture 2 Coords: x: -1685 y: 62 z: 1619