Stereo 360 capture and camera rotation

I have a camera following a spline through my world which always points in the direction of travel and I'm trying to make a Stereo 360 capture of this, but the resulting image is always aligned with one of the axis. It looks like the cube-map capture doesn't respect the camera rotation.

Is there another way I could do this (without mucking up the stereo eye separation)? If not, could this be added as a feature please? It helps to keep VR users pointing in the right direction!