BQ34Z100-G1: BQ34Z100-G1 SOC slowly dropping down at the beginning of production with no used

Dear colleague,

Now,Our company produced 20 batteries.The gauge of  battery pack use BQ34Z100-G1. The Goldenfile have  loading in the gauge flash and sent IT_ENABLE commond.At the beginning,All the batteries SOC were at about 70%---73%.Then we let the battery packs standing for 3  days.The SOC of all the batteries are slowly dropping down and Each battery drops at a different rate.Some batteries droped to about 20 percent and suddenly the SOC recover to 70 percent.then the CycleCount added 1.Some batteries could drop to 0 percen.But their are no changed in voltage,temperature and any other parameters.

I use the BQstudio loging the data of one  battery.I found that RemainingCapacity is slowly declining.Other parameters have no changed.

Then, I let one battery do one time Charge-And-Discharge cycle,the SOCis basically stable.At this time,The alternate Ratable  were also updated.

Can you tell me the reason for this phenomenon? I need your help.Thanks a lot.