The investigation continues!
Ah this helps a good deal and I think I know what the issue is, so put that Rift S back on the shelf. With the trial license it only supports 1 device running at a time. It is a floating license so you can assign it to multiple machines but it will boot you out if there is already someone using that license. I bumped this up to 2 so it will cover your workflow using two devices.
Could you give this another shot and let me know?