I had 1 spire that gave my troubles like yours. The sensors or how the sensors mount/seat can cause the popcorning issue. Basically the balls moving in the hopper makes the sensor think the gun is shooting. I had to mail it to Virtue - that didn't fix it. I ended up taking it to the booth at World Cup a couple years ago. After a few visits they finally got it working again.
I've had a couple that worked just fine out of the box. My current Spire, I had to adjust the sensitivity a little.
Best case scenario - try lowering the sensitivity.
Worst case - Send it back to Virtue or catch them at an event.