BQ24617: status error when VBAT short

Part Number:BQ24617

Dear Sir:

          I had an issue that the charge status reported is error.

the charge condition as below:

CE is enable,

VCC is 12V,

TS is fixed as shown on the schematic,

we short the VCC_M_VBAT to GND.

at the moment, the STAT1(BAT_CHARGING) is Low,

after about 30mins, the STAT1 change to high.

we measure the voltage between ACN and ACP pin,

the voltage is 4mV.

Could you kindly help to check why the charge IC indicate the STAT1 low when VCC_M_VBAT is short to GND?

Why the STAT1 is not high(Charge error)?

attached the schematic.(Please visit the site to view this file)

Thanks!