2006 (1759)
2007 (517)
2023 (2)
This is a difficult discrepancy. There are no textual variations in any of the Greek manuscripts so there is no copyist error. The best explanation I can offer is that both statements were uttered by Jairus. Jairus probably said his daughter was dying and then finally admitted that she was dead. He probably had traveled, in desperation, to find Jesus and said that his daughter was ill. Most probably, someone informed in that his daughter had died and then he told Jesus this.
The problem with this explanation is that it is not based on anything revealed in the text. Instead, it is conjecture. For now, this is the best explanation I can come up with.
Does the lack of an airtight explanation mean that the Bible is to be discarded? Not at all. We do not discard physics because we cannot understand something in it. Nor do we abandon science because of some unexplainable phenomena. As with so many other "discrepancies" in the Bible, given time, archaeological discover of more manuscripts, etc., more and more biblical difficulties clear up.