Nether Fortress generation problem

For some reason a new survival world i created in the 1.8-pre2 snapshot did not spawn chests or blaze spawners in an entire nether fortress. However, when i created a creative world to see if the same thing happened the fortress spawned like normal with chests and blaze spawners. I do not know if it was just a world generation problem or if it is a bug. Thought I might as well bring it to mojang's attention. The attached picture shows where a spawner should be. (No, i did not mine ouut the spawner)