Translating courses with XLIFF, spaces being removed by translation team

I am going through my first project using the export/import XLIFF feature. As we get translated files from the translation team (a 3rd party vendor), and import the XLIFF file, I am seeing that in some cases, words, sentences, or even paragraphs & bullets are getting run together or combined.

For example, a bolded word that, in English, had a space after it and the remaining non-bold text appear, is now a bolded word with no space after it, looking obviously run-together.

Another example is a bulleted list. In English, there may have been 5 bullets, but in the translation, it's all combined into a single bullet. This is an obvious mistake, and I found that there are line breaks in the <source> tags of English that were not maintained in the <target> tags.

I looked at the XLIFF file, and found that their translation process has (inadvertently) deleted these necessary spaces and line breaks. I can see them in the <source> tags still, but not in the translated <target> tags.

We don't have the time, budget or interest in creating a list of found "missing space anomalies", and believe that the translators should not be introducing this problem.

My question to the staff and community is: Have you encountered this before? How have you dealt with it? These are fine details that I can understand how a human translator might miss (or actually "clean up" thinking they are erroneous).