Ok, I think I found the problem myself.
The problem was that the device would wake up immediatly after entering the alarm mode.
I’ve noticed that the voltage raises to 4V2 after entering the alarm mode. This is because the GPIO47 cannot be kept on high level in alarm mode, so the Q1 is not switching, therefore the ON/OFF pin is pulled up.
If I manually keep the level on the ON/OFF pin low (0V), the alarm mode functions properly.
Thanks for the fast reply though 