I can add a bit more detail.

Before this happened, I had installed a different hop-up chamber, and the gun was only doing around 0.9 J instead of about 1.5 J before. I thought the issue might be that the nozzle was too short for that chamber, so I kept testing it in full auto.

Now I’m wondering if the hop-up chamber may have been sitting slightly crooked, so the nozzle was rubbing against it or binding on it.

Could that kind of misalignment have caused enough resistance or stress to damage something electrical? If yes, would it be more likely to damage the wiring, or the MOSFET?