LTC2942 ADC voltage conversion not correct (offset).

Hello. We are using LTC2942 in our project.
We found out that LTC2942 is producing results that are offset about 78mV (voltage reading through I2C is 78mV higher than it really is).
We measure voltage using ProsKit MT-1710 meter. 

We are using it with standard 3,7V Li-Ion battery and LTC4155 charger. 4 layer PCB.