Currently, yes, that’s how it works. We could probably consider an approach whereby the user’s set of indicated languages is compared against the list available based on the journal settings, and an appropriate match is chosen, but I’d worry that Journal Managers are likely to fine-tune wording only on the primary language, so they might not be aware that emails are going out in other languages with the “stock” OJS wording. This is related to another recent question on the forum:
Regards,
Alec Smecher
Public Knowledge Project Team