In “facta sunt peccata”, “peccata” is the subject (peccatum, peccati = fault, error, mistake, blunder, sin) and “facta sunt” is the verb (facio, feci, factum = do, make, act). Although if I’m not mistaken, “facta sunt” is the present indicative passive, so “facta sunt peccata” = “mistakes are made”. I think it should be “facta erant peccata” for past tense.
I can’t answer the questions about how Google translate works, except to note that it usually works poorly.