capacitive reactance in a stranded wire
All wires have a distributed inductance and capacitance and a resonant frequency which becomes a short circuit at 1/4 wave and beyond this inverts the wire reactance and impedance rises to the free space impedance at 1/2 wave length and then repeats.

This is the characteristic of a whip antenna.

So it depends on the length of wire and what f was used in the test.

The wire is inductive based on ratio of length to diameter and capacitive based area/gap ratio with the ground signal.  So a single wire is fairly low pF /m compared to loose twisted pair which is ~ 50pF/m.

Conclusion:


measurement error or at least ill-defined measurement conditions.


Although proximity of wire to hand or any dielectric that is grounded by stray a capacitance will affect pF/m.