On firmware 6.3.1 build 3138, when I set Security to HTTPS and apply changes I can navigate back to System and it looks good. If I navigate away from System and then back again, the settings are back to HTTP and Web Admin Access is back to LAN/WAN. Any idea why the setting will not be retained?
Is your router managed in InControl2? I noticed that happening to me and it was because IC2 was overwriting the configuration.
Yes - I manage them via InControl2. Did it turn out for you that LAN only was not an option when using InControl?