Commenting on the death of Judas Iscariot, Matthew 27:9-10 reads:
There is no such verse in Jeremiah. Matthew is instead (very loosely) quoting Zechariah 11:13:
There are two problems here: the difference between the quotation and the original source, and the fact that Matthew gives the wrong name of the source. This could be another scribal error, but in this case even the NIV, which is normally very eager to resolve contradictions, gives the text of Matthew as above. The notes to the NIV are pretty desperate though: they give as cross-references Jeremiah 19:1-13 and Jeremiah 32:6-9, the only connection with Matthew being that these verses contain the word "potter" and the purchase of a field, respectively.
The Apologetics Press (link below) suggests that, since the prophecy was "spoken by Jeremiah", this does not actually refer to the writings of the Old Testament at all, but simply to a spoken prophecy that Matthew is somehow aware of centuries later. Alternatively, they suggest that Matthew refers to the book of Zechariah by naming the first book in the sequence of prophetic books.
There's a much simpler explanation: Matthew made a mistake. The problem with infallibilism is that you have to adopt complicated explanations far too often.