If I have two articles with the same name, only one will show up in search. This includes all searches: as a user viewing the world, the search bar at the top of the dashboard, the search bar on the articles page, and the mention system (the autolinker still picks up on two articles and works properly, it's just the auto-complete for mentions that doesn't show the duplicate).
search for a duplicate article name in any of the search bars on the site, or start typing a mention for an article name with duplicate articles.
I mistakenly reported this also. I have seen where you can display articles by 'Type" to find them, but that is cumbersome.
I have just encountered this same bug with one of my articles. Both have the same name but only the one using the generic article template appears when searching. The other is using the technology template. I have found that if I click the full search in Athena then I can get both to show up. If the team needs a world for testing purposes, feel free to ping me in the IS chat.
Also mistakenly duplicated this (fitting for a bug about duplicates). Big problem imo.