Chests had repeating loot in specific areas

I was in a single player world, and I visited a nether fortress. The nether fortress nearby had a few chests, but the only had two types of loot. Either it had 2 diamonds and 1 flint & steel, or a saddle and a golden chestplate. At first I thought I was lucky, but then I realized after the 4th chest in a row that this is probably a bug.