There are such cases in the Talmud too—quotations of verses that differ from the Masoretic text. Rabbi Pesach Finfer, a halakhic judge in Vilna, wrote an entire book about this. In my humble opinion, in literature of such scope there can be quite a few mistakes due to habitual phrasing; after all, we are dealing with only a few manuscripts that survived. One must also take into account that, unlike today, the copyists did not have computerized “databases” before them that made the entire body of Torah literature accessible at the click of a button.

Best regards,
Shatz