How to reproduce

• In the search box, enter 'wikibugs'. One project ( https://phabricator.wikimedia.org/tag/wikibugs/ ) is returned.
• In the search box, enter 'wikibugs irc'. Two projects ( https://phabricator.wikimedia.org/tag/tool-labs-tools-wikibugs-irc-bot/ and https://phabricator.wikimedia.org/tag/wikimedia-wikibugs-irc-bot/ ) are shown, both archived.

On IRC, this is suggested to be by design:
20:03 <btrahan> I think the idea is if you're searching and it can find open / active stuff, it does
20:03 <btrahan> if there is no open / active stuff, it will show you archived / closed stuff

however, the interface needs some work, e.g. by showing the projects as strikethrough.

Upstream bug: https://secure.phabricator.com/T6906