I was playing the solo story mission, Algorithim. After activating all the fumigation pads in the first room, I died because I didn’t get out in time. When I respawned, Geoff wasn’t outside in the courtyard. Instead, my map indicated he was somewhere near the entrance to that first fumigation room, but he wasn’t on the screen. When I moved near where the red icon indicated, he would taunt me, but that’s the only indication he was around.
Eventually I used up all my lives in the fumigation room looking for him. The next playthrough I realized if you get out in time, he appears in the courtyard, and everything was fine.