Unity/Rift black "viewing area" curve on right side of screen

I recently updated to Oculus Integration v38 in Unity. When I build for PCVR and press "run" in the editor, I'm seeing the black VR "viewing area" curve on the right side of the screen. It doesn't occur if I build the same scene for Quest, and for Rift S, I only see it in the editor game display - in the headset, it's not there. It's only a distraction/annoyance - is anyone else seeing it? If so, have you found a setting to get rid of it?