How does one make Stereo Rendering Path Single Pass function properly in VR?

Whenever we enable Single Pass (Fast) rendering in the PlaySettings / Stereo Rendering Method option, it produces a split screen which messes up the visuals in both Oculus and HTC Vive / SteamVR HMDs. Is this option capable of driving VR HMDs, or should we always use “Multi-Pass (Slow)”?

I realise this was literally a year ago today, but I just had this issue and it was because I was using the post processing EdgeDetection script (only supports multi-pass), without that it works normally.
Hope this helps somebody that stumbles across this.