BUT, why would the Earth Current NOT take the path of least resistance through the Ground Wire instead of going through Earth? Still puzzled about that! The AC wiring at the Bonding Point and the Ground Rod wire combo may be serving as a small scale step down auto transformer.
EDIT 1:
Just as we have stray capacitance in the RV wiring, we may have stray inductive coupling in the Breaker Box where the N/G Bonding takes place causing a small voltage to develop (ie 0.4 and 2.2 VAC) in the wire to the ground rod..
EDIT 2:
To really get to the bottom of this we would probably need to consider all stray inductance and capacitance all the way to/from and including the Power Transformer on the power pole.
End of story for me.
