Hi John,
I have always checked the insulation where it comes through the cap. That is why I caught off guard.Twice. LOL.
My issue seems to be the hot end of the resister was grounding not the lead coming through the cap.
My solution was order some 1/16" and 1/8" braided ceramic sleeve rated for 2600 degrees. I will add a short length to cover that end of the resister.