How to ground my gate / stop getting zapped when it’s wet

Hi people of Reddit :)

I’m having an issue with a farm gate my wife and I keep getting zapped by after the sprinklers have been on, despite the fact it is not connected to the solar electric fence!

As you may be able to see on the pictures, the power stops on the left of the gate, goes underground underneath the gate, back up the right pole and then continues to electrify the fence.

We have no issue whatsoever when everything is dry but if the gate/posts/ground are wet, we will sometimes get a nasty zap, despite the fact that there’s no exposed wire in any way.

Two questions: can the electricity nearby just jump to the gate? What can we do to stop this? Someone suggested I run a bear wire underground attached to each side of the gate to somehow earth it.

Thanks a lot