Was the resistance decreasing with line voltage (rather than the 3VDC test voltage in the pic)?
Could be, Virgil.
The GFI electronics will most likely be fed via a full-wave silicon rectifier assembly, each of the two diodes in the path needing about 0.6V to fully saturate them. Add the extra PN junctions in the circuitry, and 3V may not be enough to give you a true indication of what the resistance will be when 120V is applied.
Another point: Did you try reversing the meter probes to see if you got the same reading? Don't forget that with the DMM you're testing with DC.
