Firmware version is the default that came with it out of the box 3.023 compiled on 2019-05-23.

I only changed WiFi SSID and password first for 2.4ghz and password (using hit Modify, then Save). Router disconnects and restarts.

I then connect to the new SSID, then modified the SSID for the the 5Ghz (using hit Modify, then Save).

After a day or so… all I did was just unplugged power adapter from wall. Then replugged in.

When I do that, all the settings reset to factory and it asks me to define admin password, etc.

I redefined everything using the same process above and it works fine… but then I unplugged the power adapter from the outlet and replugged in, and it forgets all the settings and auto-resets back to factory settings again.