"Matthew’s account of this incident (Matthew 27:7f) has been alleged to contradict what Luke said here; but, in actuality, the two accounts are in perfect harmony. Judas hanged himself, as Matthew related; but his body also fell, as in Luke. We do not know whether the fall took place as a result of Judas’ bungling efforts at suicide, or if his body hung until it fell of natural causes. Tradition says that he fell while in the process of hanging himself. Johnson says:
He probably hanged himself on a tree projecting over the precipices of the Valley of Hinnom, and afterward, on account of the rope or limb breaking, fell headlong with such force as to burst his body open on the jagged rocks. This is the traditional account of his death.[23]
Such alleged “contradictions” as skeptics delight to point out from such variations in the holy gospels are called “pseudocons,” which means sham-contradictions, being, in fact, not contradictions at all but variations expected from independent accounts of events in the New Testament."
studylight.org/commentary/acts/1-18.html