I had the same problem yesterday. All of a sudden it stated critical low voltage and started to land. Luckily I wasn't too far away and was able to land. Messaged DJI and they said fully discharge the battery and recharge, but I certainly won't be using that battery again.
As far as I can see, my mistake was to recharge the battery partially to around 60% and then fly. I've done about 150 flights in total, without any problems, and wasn't even aware that the battery's need to be fully charged before flying.
I'm assuming it's ok to fly for around 10 minutes for example and then fly again on the same day with say 50% charge, as long as the battery wasn't just partially charged initially ??