One funny thing that I found not long ago is that you can traverse a long chain of word translations by re-feeding the translated word. You start with a word let's say in italian, get it translated to spanish. Now you grab that word in spanish and translate back it to italian. You do sometimes a get a different word. You do this again and again. There doesn't seem be a one to one correspondence in certain cases. Don'…
Yes it is well known, but I wouldn't call it an issue per se, but rather a demonstration of the ambiguity of natural language. In any given language, many (most?) words have multiple meanings. Even if one of the underlying meanings of each word in your translation chain is "equivalent" (this could be a deep philosophical discussion of semantics on its own), each word-to-word correspondence for each language-pair has a different most-probable choice in the translation model (especially without context to help disambiguate).