Dynamic DNS shows Hostname that is not define
If #8948 is not a bug, then this is:
In the overview there is a Hostname shown when you write one into the hostname field and change to Custom afterwards. As Jim said that custom configs don't have a Hostname, and the field is not shown when configuring a custom URL, no hostname should be shown in the Overview afterwards.
However, I'd rather prefer considering this as "not a bug" and re-opening #8948. One of these is definetely a Bug.