Again, I don't have the info. If the pilot armed his cannon while inbound to the range (simple electrical switch) and a short-circuit happened (very easy thing), then that could cause the cannon to fire early. It would probably be a repeatable thing and relatively easy to prove, although intermittent electrical faults are a pain to troubleshoot.

Basically, there are only a couple electrical switches in the firing circuit, the arming switch and the trigger. Switches can and do fail from time to time. Electrical circuits can and do short out from time to time (the F-16 used to have serious electrical wiring chaffing problems that caused several crashes back in the 1980s).

Not everything that happens is deliberate. Odds are there is flight recorder data to help confirm the story. If he did screw up, he's toast.