Error when importing XLF file for Course translation

Today I got to know this:

"If your course contains empty lessons or blocks, the import will fail. So you'll want to delete any empty blocks/lessons. And if you do, you'll need to re-download the translation file from Rise, run the translation again, then import the translated file to Rise to complete the translation."

This seems "easy to fix" but cost us money and time due to another contact with the translator. - an "external supplier" to our client . It means that we need to order another file from their translator? 

Many would be helped if you add information about "make sure there are no empty blocks in courses to be translated" and "do not change anything in the course copy after exporting xlf in Rise for translation". This info is needed before the first xliff export from the "specific course copy" in Rise.

Regards,

/R