When a page that was already translated, now appears again in the original content it is usually because the original web page content have changed since it was translated.
Bablic detects phrases according to their actual content. If a content was changed in the website in the original language, Bablic will identify it as different content. Naturally, this new phrase will show as not translated.
You can open the Dashboard Text Editor to search for new untranslated contents.
You can tell Bablic to associate an HTML element with a specific phrase. To do that use bablic-id attribute from the Markup API.