Hi, Seems like apples and oranges, I’m using successfully the “double tap” for interrupt generation and the accelerometer config to generate it. and for the shut down or sleep, the most important is the delay after
nrf_gpio_cfg_sense_input(digitalPinToInterrupt(int1Pin), NRF_GPIO_PIN_PULLDOWN, NRF_GPIO_PIN_SENSE_HIGH);
delay(2000); // delay seems important to apply settings, before going to System OFF
NRF_POWER->SYSTEMOFF = 1;
otherwise the system wakes back up immediately.
My demo with code will stay asleep for as long as I don’t touch(Tap) it. 2-3 days easy.
HTH
GL :-p