Reminds me of an RTI system that a member here asked for help with. I uploaded all the devices in three rooms and the system just made zero sense... and could not have worked. Finally in one room it occurred to me to follow a wire and I found an RP6 (if I remember that model number correctly). Once uploaded, the entire system made sense.

You've got to trace what wires you can. "can't find it" can mean a lot of things, from "I'm too old for this shit" to "I've been through the entire attic and have followed that cable around under the eaves...[this just goes on and on until the thing is found]"