Thread:Support/zh-hans characters 创建账户 , even though we are a zh-tw site!/reply (3)

It's. A list of all translations is at Special:Translations/MediaWiki:Logentry-newusers-newusers. As you can see, there is no translation for that message in Tranditional Chinese yet. So better create a translation in zh-hant to get it fixed; MediaWiki does what it should do: respect the fallback chain.