MAX1724 shutdown only implies that the chip is not operating. Since the device is not true shutdown, there is still a path between the input and output. From the datasheet (rev 5 8/17), "During shutdown, the body diode of the P-channel MOSFET allows current to flow from the battery to the output. VOUT falls to approximately VIN - 0.6V and LX remains high impedance." If you need a true shut-down step up converter,
please refer to the MAX8627 for a 5V output.