I haven't attempted latin translations, but anything from my native language to english and back has been 100% perfect, miles better than anything google translate can do
Not exactly sure why, maybe small corpus, maybe because it's a pro-drop language without fixed word order and an very complex set of conjugation rules.
That's probably most of the problem. The entire corpus of ancient Latin is on the order of 9-10M words. If you printed it at the same density as a typical English novel, it wouldn't even fill a bookcase.