Bug Multipass only does multiple passes on final camera

Is there a way to choose which camera will go through multiple passes for each eye (and have the correct camera offset).

I have a VR camera that renders to a texture which has the final output camera pointed at it (so I can perform shaders on the texture and have UI elements in front that are unaffected).

The issue is that the VR offset between the two eyes only seems to happen on the camera that renders to the headset. Since the output camera is pointing at a flat texture, all depth info from the scene is lost.

Is there a way to force the first camera to also multi-pass render with an offset?