sd_power_system_off goes directly to main() in sdk5.2

[julian]

  nrf_gpio_cfg_sense_input(IO_PORT_INT_BUTTON, GPIO_PIN_CNF_PULL_Disabled, GPIO_PIN_CNF_SENSE_Low);
   APP_ERROR_CHECK(sd_power_system_off());

after sd_power_system_off, it goes directly go main, but in Sdk 4.3, it has no problem to put to system off. Any possible causes? Thanks!