In a recent code change we've prohibited the creation of lowercase topics. So all=BASETOPIC= references in the "Not found" page already start with uppercase. Yet we are redirected to WebTopicNonWikiTemplate that gives the warning:
WARNING: This topic name is not recommended because it will not be linked automatically. See WikiWord for details
I think this can be removed.
As Kenneth rightly states: "TWiki" is also a non-wikiword. So the message remains.