Charles Ellicott Commentary 1 Chronicles 6:50-53

"And these are the sons of Aaron: Eleazar his son, Phinehas his son, Abishua his son, Bukki his son, Uzzi his son, Zerahiah his son, Meraioth his son, Amariah his son, Ahitub his son, Zadok his son, Ahimaaz his son." — 1 Chronicles 6:50-53 (ASV)

If the chronicler, and not his source, is held responsible for this repetition of the Aaronite line, we may regard it as an instance of his artless method of making a new start. He is about to pass from the Levitical genealogies to their cities and domains, and he first partially recapitulates the line of Aaron’s sons, because their settlements are to be described first. (Compare 1 Chronicles 6:1–2 with 1 Chronicles 6:16, 18.) He stops at Ahimaaz, who lived in the age of David and Solomon, because, apparently, the preceding section was mainly concerned with the Levites of that epoch.