Uh-oh, thanks. When Flow gained the Topic namespace I checked for conflict with existing wiki pages in the main namespace named "Topic:something". I thought at the time I checked for existing namespaces named "Topic", but enwikiversity and jawikiversity have had 'Topic' namespaces for a while. Sorry.

Both checks are now mentioned in "Steps in activating the Flow extension on a wiki" [1] (I assume this is missing a lot of other things y'all do these days to Flowify.)
 

Around 2014 there was a language in which the translation of "Topic" (in extensions/Flow/Flow.namespaces.php ) conflicted with an existing namespace translation, I think the translation was of "Project" but I don't think it was the fa (Persian) translation, as I recall it was something non-Roman like Cambodian. Paging the Quiddity memex service... :)