This is not a bug.
The camera is needed at least for raytracing.
Just make a temporary camera that will be used until your VR camera is initialized.
Then you can replace OnlineMapsControlBase3D.activeCamera.

NullReferenceException: Object reference not set to an instance of an object
OnlineMapsTileSetControl.HitTest () (at Assets/Infinity Code/Online maps/Scripts/Controls/OnlineMapsTileSetControl.cs:646)
OnlineMapsControlBase.Update () (at Assets/Infinity Code/Online maps/Scripts/Controls/OnlineMapsControlBase.cs:740)

I am guessing HitTest is called automatically by OnlineMaps and it is not finding the camera? There is no camera setup in the scene until the scene knows what VR SDK/device the user is using. But the error still continues each frame once the VR camera rig is up and running (and the camera is marked and MainCamera).