Bluetti EB3A sudden drop to 0%

New Bluetti EB3A. Have lightly tested it. Charges from wall ok; charges from car ok; ran a 300W coffee maker ok. I was using it to heat up some food using a 12V “electric lunchbox” using the Bluetti DC ‘car’ port. It was running fine for 30 minutes exactly. The charge had dropped from 48% down to 37% in that 30 mins, again, ok. Then, it abruptly dropped to 0%! Why did it suddenly, literally in the blink of an eye, go from 37% to 0%?? I am currently recharging the Bluetti using AC/wall outlet. And, it seems to be recharging fine. But, this scares me. Is there some kind of explanation or do I have a defective Bluetti?

@mjc Is the temperature too low? If the temperature is low, the cell voltage will drop significantly during high-rate discharge, which can easily trigger undervoltage protection.

Thank you. Ambient temp was ~65 degrees…‘room temp’.

@mjc If it is not the problem of temperature, please do a full cyclf of charge and discharge.