I did my translation manually, using Poedit, and the strings you mentioned are translateable there.
The process is as follows:
1. download learnpress.pot file from …/wp-content/plugins/learnpress/languages
2. open it in Poedit that you downloaded for free and choose the translation language
3. translate all strings, or perhaps it can also work if you try just those you need
4. save the translation and two new files will be created: one .po and one .mo
5. upload .po and .mo to …/wp-content/languages/plugins
But I could not find strings ‘passed’ and ‘failed’ after a test is finished. Could you translate those in Loco?
Gala