glSubImage issues with Sparse Textures

I am trying to implement the example in the github apitest into our renderer at work, and am having issues with Virtual Pages not receiving the correct image data. I describe the behavior in the opengl forum here:

Is there missing logic in apitest for dealing with virtual pages, or is this a driver bug?

I am using Ubuntu with MacBook Pro GeForce GT 750M. Drivers: 331.113