Why don't you turn on Balance?

Please check whether you have set up dynamic balance or charge balance. 

Charge balance: Balance will only be activated when there is a charging current, and the battery reaches the set balance voltage with the maximum and minimum cells reaching the specified voltage difference. 

Static balance: Balance will be activated when there is no charging current, and the battery reaches the set balance voltage with the maximum and minimum cells reaching the specified voltage difference. Balance is required.