Texture on my custom hi-poly sphere maps with strange splits and holes in the poles

I'm using Shader Forge to resolve an issue with Bumped Diffuse in Unity; apparently it is mutually exclusive with soft shadows. Creating a shader with SF resolves this wonderfully. But if I use a custom, hi-poly sphere I created in Maya, the texture maps in a very strange fashion: the texture is split longitudinally across the sphere and there are small holes in each pole. I can't figure out why this is the case; both the shader and the model are extremely straightforward and basic. The built in sf_sphere works great, but it doesn't have the level of detail I need.