I've had numerous problems with the round plastic end insulators. My fence checker would show a short at that end but you could not see anything wrong. Finally changed the plastic end insulator and when I had it off you could see it was cracked inside, burned and shorting out internally to the support wire.

So went to using round ceramic thinking these were better but recently had a similar problem with one of those - cracked inside and shorting out but you could not see or hear anything...

The only end insulators I have never had a problem with are the cylindrical ceramic, Gallagher makes them I believe.  There is evidently more ceramic material between the hot and support wire paths that they are less prone to internal cracking and shorts....at least so far.

With the Gaucho maybe the barbs are shorter or something but I have had regular barb wire crackling like crazy when the weather is a bit damp or humid, arcing from the ends of the barbs to the side of a tee post if the barb happens to be oriented a certain way. Switched to smooth wire only for electric and no arcing problems regardless of type of post.

This type of thing gets exponentially worse as you go to a hotter fence charger.  All those volts are just looking for a place to get to ground.

And the bigger/higher voltage/higher joules the charger, the bigger a gap it will arc over.  I think this accounts for some of the different experience folks describe on here whenever this topic comes up.

Jim at Dawn