LAOTIE ES19 - Battery problem - part 3

When the chargers are green the voltage it's 61.9 volts.
when I unplug the chargers and I try to ride the scooter with a single motor the battery discharge very fast.
maybe there is some faulty cell on the battery because this behavior didn't happened before.
In the beginning, when I bought the scooter the full Battery was 67.2 volts when it was full charged.