Floor plane with reflections in offscreen render

[exilef]

Is there a way to get reflections and shadows working in an offscreen render?

I have tried adding a SCNFloor node with reflective properties. While both shadows and reflections show in the rendering produced by SCNView, the reflections are not visible in the offscreen rendering. Some magic going on in SCNView that is not exposed via SCNRenderer?

Example below (top: SCNView rendering, bottom: result of offscreen rendering). Any clue appreciated, updated example is here: https://github.com/exilef/SceneKitOffscreenRendering

Note also the weird shadow artifacts in the SCNView - in contrast, shadows seem to be correct in the offscreen version.