Commenting on the JST (here, called the "Revision") and how it is often a hit-and-miss attempt by Joseph Smith at harmonisation of parallel accounts, Reed C. Durham Jr., wrote:
The text of Mark 15:28 in the Revision contradicts that in John 19:14-16. The latter states that Jesus had not been crucified before the sixth hour; the passage in Mark states that his crucifixion was at the third hour. 1 Kings 4:26 relates that King Solomon had “forty thousand stalls of horses,” but 2 Chronicles 9:25 reveals that he had only “four thousand.” . . . He revised Genesis 5:32 of the Authorized Version (Revision, Genesis 7:85) in such a way as to inform the reader that Japheth was the eldest son of Noah; but he corrected Genesis 10:21 of the Authorized Version (Revision, Genesis 10:12) to reveal that Shem was the eldest son. Joseph Smith significantly altered a passage located in 2 Chronicles 18:20-22, but had apparently overlooked that same passage in 1 Kings 22:21-23. It is apparent that Joseph Smith went to great lengths to harmonize the Gospel accounts, but occasionally failed to correct apparent errors. He corrected Mark 10:11, but failed to do the same in Matthew 19:13 and Luke 18:15. These are only a few of the passages which offer evidence of the incompleteness of the Revision. (Reed C. Durham, Jr., “A History of Joseph Smith’s Revision of the Bible,” Ph.D. dissertation, Brigham Young University, 1965, pp. 128-29)
For more, see, for e.g.:
Kevin L. Barney, The Joseph Smith Translation and Ancient Texts of the Bible