No I never sorted it out, I gave up when I replaced it and it fried again. Fortunately I found a buyer (a model home in a new community being built) that didn't give a shit/would never notice if that gate works so I gave up.

I DID however come up with an explanation that I thought was the issue...I believe it was the opto at the gate that triggers the small gate coil. I think that opto was intermittent, and was rapidly turning the coil on and off over and over, which was frying the gate, as it's not meant to be used that way.

I'd be paying close attention in switch test to that opto switch and see if it was rapidly triggering on and off. It could be a dirty opto/out of alignment, or something else like that.