I had ordered a SIM from them, then threw it in the drawer and promptly forgot about it. I'm going to see if I can find that again, thanks for the reminder.

140 is a little light but yah, it's definitely a solar thing only. It's possible it bounced over the 150 for a very short time to trip the cutout, and the 140 number you're seeing is a time-smoothed average in your reporting system. If you're using something trustworthy like a Smartshunt to get that data, then yah, tripping 10V short isn't great.