Hi there Lucas, thank you for submitting to our Ucraft Forum!
The mentioned functionality is not a bug; it is how syncing works in between different language versions of your website. The thing is that the duplicated page is only being live for that specific language, where you initially duplicated it. The rest of the pages, duplicated for other languages, are automatically set to offline, meaning they don't go live until you manually publish them.
Hope this helps!