I am inclined to try and raise up that caudex some more maybe and add that copper fungicide as well. Sometimes it helps. Yours is in the ground already, which is good, so maybe improve on that site's soil around as well. Maybe it is getting too wet which causes the caudex damage?
I have seen one of my younger cycads with very bad caudex growth, leaves dying off. But I had it in a self watering container then and planted too deep. It was easier for me to pull it out, change to a better draining container and made the media grittier. In time, it grew a new caudex on top of the older damaged caudex. Just had to wait very long and patiently for this recovery and the new flush of leaves every summer.
My suffering little cycad Sept 2011
After the changes I made, it grew much better, a real long wait but well worth it.
26 Aug 2013
You can clearly see the new caudex on top of the old caudex.Had to keep watch as it grows, at times I have scale attach on it, have to do alcohol/dishwashing soap/tabasco sauce swab
24 July 2014