I originally configured the Advanced>DDNS setup to use noip<dot>com with a domain named  "name1<dot>ddns<dot>net". I should have used "name2<dot>ddns<dot>net" as "name1" was already being set by another router in another network. This error caused the "name1" entry to be overwritten in noip<dot>com, which of course was undesirable.

I edited the settings and changed the name to "name2<dot>ddns<dot>net". I now observed "name2" to be set with noip<dot>com. I manually updated "name1" to the correct address. Several hours later I found functionality related to "name1" to no longer work. Checking noip<dot>com I found the both "name1" and "name2" were being set by the deco system.

This is incorrect. After the edit, the "name1" entry should no longer have been touched. It appears the firmware, incorrectly, now has two DDNS setups to update. Unless a firmware update comes soon, or a workaround is available, I will have to factory reset the whole setup just to remove this problem.