In passive cell balancing (aka bleeding), some charging current is dissipated inside the battery pack.
Thus, balancing decreases the real pack SoC.
However, the gas gauge, from a coulomb standpoint, is blind to that loss. Therefore, it may not adjust the SoC accordingly.
Can you give me some details on how SoC is handled in face of cell balancing?
I am especially interested in bq78350/bq76940 combination.
I also consider using bq34z100 for fuel gauging with an external microcontroller to glue all that together.
Regards,
Frédéric