A-5 e-grip trouble

I went paintballing this weekend and let one of my friends use my A-5 with e-grip and JCS adjustable trigger. For the first two rounds the gun worked great, but during a break for water the A-5 randomly started shooting. The safety was on, and the trigger was untouched. After it did that, when I pulled the trigger I could feel the switch being tripped, but it wouldn't fire. I took the CO2 tank off and put the gun down on a bench and started to dig through my gear to get a new battery and I could hear the solenoid randomly clicking with the gun just sitting on the table and no one touching it. I put a fresh battery in it, but it kept doing the same thing. After I changed the battery, I thought maybe the trigger was set up wrong so I played around with it, and I could feel and hear the switch being tripped but the solenoid wasn't firing. I eventually decided to just put the A-5 back in the truck and have my friend use a rental the rest of the day.

After we decided to call it day and go home, I took the gun out again and tried to figure out what was wrong with it, but then it was working fine. I played around with it the rest of the way home, but it worked as it was supposed to from then on. I have no idea what was wrong with it or why it started working again. It was a kinda hot day, but I've played with it before in hotter weather with no trouble.

I only have a few upgrades on it, the e-grip with the JCS trigger, and a JCS folding stock with RVA. I was using fresh Duracell 9 volt batteries.

I think I had a problem like this before, and what caused it was the amature pin