Describe the bug
I found a structure generated such that it carved a huge square out of a lake, when it shouldn't have had trouble placing it on top of the terrain since it's just a flat grassy biome. (also, sea level is set at the normal level.) I'm using OTG with a preset of my own creation. I've seen these generate normally as well, not sure why this one is so low down.

To Reproduce
This is the first time I've seen this - I think it just happened randomly, I'm not sure it's directly reproduceable.

Expected behavior
Structure sitting on top of the terrain

Screenshots

Versions
Chocolate Quest Repoured: 1.6.1A
Forge: 14.23.5.2838
Minecraft: 1.12.2

Other
Crash report: no crash
Log file: no crash
Singleplayer/Multiplayer: singleplayer
Other mods (that are necessary to produce the bug): possibly open terrain generator (v8.3)
Other mods (that are also installed):
XL Food Mod
ResourceLoader
Beasts
DungeonMobs
ExtraCreatures
FertileSoil
llibrary
LootGames
OpenTerrainGenerator
PizzaCraft
rustic
sbirds
TimeCore
walljump

At first: You are using an outdated version, we do not support outdated versions.

Second: This actually isnt a bug, it is just that we forgot something in the structure placement which chooses the y coordinate. In your case the dungeon position hit the ravine and it then chose the highest y at that coordinate which was the bottom of the ravine.