In the Firewatch sewers, when entering Uriel's Quarter from Old Fortress, I fell through the floor. I tried tcl to get back to open space, but after disabling it again, I kept moving as if I was jumping. Upon further exploration, I found an NPC (Elatius Nistrius) also "swimming" under the floor. I also tried the Fort Symmachus->Uriel's Quarter entrance, and did not fall through the floor, but Elatius was still underneath it.