BQ76940: bq76940 Cell Voltage Measurement Error

Part Number:BQ76940

I'm testing one of our prototype boards base on BQ76940 and the output of cell voltage is not correct:

Output of Measured Voltage:3586,3632,3606,3624,3668,3626,3604,3661,0050,3656,3670,3663,0046,4014,0046

Actual Voltage:                      3586,3632,3606,3624,3668,3626,3604,3661,0000,3656,3670,3663,3600,0000,3600

I have measured the voltage across the pin of chip vc12-vc13 = 3.6v，vc13-vc14=0v , vc14-vc15=3.6v ,  seems correct.

Even more, the balance FETs  haven't been welded.

Any ideas on the possible cause would really be appreciated. Thank you for your help,

Albert