I took no offense at all. And I hope none of my replies seemed terse, tone deaf postings I'm afraid.
Whether your regulator is wonky or not, you really need to check whether or not all of your components in that tray are secured from sliding about or possibly grounding out against each other. Your regulator may be damaged now due to the fire, so that's not a guarantee to the original cause.
If everything feels secure, then you'll have to start looking for a faulty component, checking your wiring harness for melted spots, etc. And make sure you've used shrink wrap or other sleeving on the terminal ends in your tray to help isolate the components from each and the metal tray.
I am always suspicious of these trays being possible electrical shorts should any contact occur whole riding. I'd use the foam pads that came with the Shorai to insulate the interior sides, and the components on the bottom, then secure them. Reduces vibration, helps them stick tight to their location, and insulates them from the tray as a grounding or shorting material.
When you get the courage up, take heaps of pictures and I'd bet you'll see the origin.