Dungeon spawned in my house Hexxit

[PandaGirl]

So my brother and I have built a huge house with so much loot. We recently took a trip to the Nether, and when we returned we found 3/4 of our house cut and gone, a netherrack dungeon taking it's place. Most of our chests, enchanted armor, enchanted swords, important items are all gone, as well as a lot of ore and staffs. Is this a glitch or part of the Better Dungeons mod, because my brother and I are really angry and upset.