Missing Knowledge user permissions

If you can find the Translation Request record associated with your translation complete (status = Message Translated), but your translated version still haven't updated from the original language, it is likely that the Integration user (who installed Unbabel) is not a Knowledge user. 

Assign the the permission "Is Knowledge user" and recover the translation.

Duplicate translations

Another cause for a translated not to update its text is the existence of a simultaneous Translation Request records associated with the same article for that particular language. If an article was stuck with an incomplete (or even complete, but failing to update the text) previous request, a new successful translation will fail to populate the translated content.

In order to check if this is the case, access the Translation Requests view or run a Report on Translation Requests to confirm if there are duplicates for your article/language. If you find any, keep the latest completed record and delete all previous ones. The content should update then.