In order to edit the translations for a language, a user must be a member of that language group in Zanata.
Project owners were unable to edit the translations in their own project, unless they became a member of all language groups for which they had translations. This made applying an update to all translations in a project difficult.
Project owners were given the ability to see and edit all language translations in their projects.
Project owners are now able to edit all language translations in their project without joining multiple language groups.