I have had my Pico "not" stop firing after I released the button, twice now. Both times I pulled the battery out and put it back in and it worked properly again. Both times, perhaps just a coincidence, when I put the battery back in, I noticed that the battery bar was all the way down, or close to it (3.5V-ish on my charger). Anyone have this happen before?
Not on any of my Pico's, but just recently on one of my SMY SDNA75's. Evolv replaced the board for free, no questions asked. I know that doesn't help you much, but it might be the board going bad.