So I created a double V belt drive using the belt function in SolidWorks. Now after installing the shafts on the pulleys, and the gearbox the belt has to drive, the belts are not on the pulleys anymore. The pulleys are still concentric with the belt, but the belts have shifted to the side. Rebuilding doesn't fix it. How the hell does this happen and how can I fix it?

I attached the whole assembly to this post for those of you who want to have a look.