In the past week my home security system is playing havoc.

Whereas before the Security App showed only IPv4 parameters and IPv6 entries were disabled and blank, now there are partial entries for IPv6 settings. I checked the Security App and the IPv6 cannot be deleted or disabled, and the settings are reported "incorrect" , and I cannot remove IPv6 entries and I cannot Save unless DCHP is permanently ticked as "disabled". What a nightmare!

I would like to rid myself of all IPv6 options and stick exclusively with IPv4.  Meanwhile all my security system is not working.  How to I revert to exclusive IPv4 operation?