The translation issue occurs because:

1. At the time you were trying to share, the language string isn't translated.
2. After noticing this issue, you translated the content.

What you are missing is the following steps:

3. Because Facebook cache all urls that are shared on their site, these untranslated strings are also cached.
4. You need to follow the steps below to purge their cache

Purging cache on Facebook
1. Head on to http://developers.facebook.com/tools/debug
2. Enter the url that you were trying to share
3. Click on the "Scrape again" button to purge the cache