Zyxel Switch Configuration Lost After Power Outage or Power Cycle Issue: This is current design. This is normal because settings are set temporary in Memory of any Zyxel Switch. We require that the user saves the configuration into flash prior to power cycling the unit.
If power is cycled or lost prior to saving the configuration, the device will fallback back to the last saved configuration...which can be the default of device.
You find the "Save" button in the upper right corner of the web GUI.
Example on a GS1900-8HP:
Example on a XGS4600-32
Be sure to save the configuration after setting up the device as desired.