After a few weeks of testing and getting through the majority of the app a bug has been revealed when switching specifically from AR to VR.
What seems to happen is that the field of view is too small for iOS, this is not an issue on android however.
I have uploaded the image, nothing in particular is done to modify the field of view or anything in particular to the vuforia camera.
The UI is attached before vuforia is enabled so that switching into stereo applies to the UI display. As you can see the image collapses in the center which is not comfortable in VR.
I think its the field of view as mentioned, but there could be other factors. It does start up with a slightly different field of view and not long after goes into this effect, but even the before is no better.
Any help with getting this sorted would be great. Anything that I can do to make vuforia force the resolution/fov to be the correct value regardless of the "best" view for the camera?