Attached is a demo file of a map object I took from SUPERNatural and turned it into a model.
When loading up the game, every time the bobbing lights reach the top of their bobbing, the entire tower will rotate 90 degrees immediately and turn.... and this is where things start to get a little nutty. The "shape" or "direction" of the GL lights also changes and gets all sorts of weird, like it's partly a spot light, though it's simply an attenuated point light.
For the record, made sure this model was as clean as possible, ensuring there were only tris and quads that are clean all over. If needed I can supply the model too, in .blend format.
You do not have the required permissions to view the files attached to this post.