Geshur and Aram took the towns of Jair from them, with Kenath, and its villages, even sixty cities. All these were the sons of Machir the father of Gilead.
Caleb here is plainly a shortened form, so all exegetes recognize it. The first half of verse eighteen is obscure and likely corrupt in the text. We must read it as 'Caleb begat with Azubah' and separately 'with Jerioth', one was his wife, the other a secondary partner, and only one wife's sons are listed before her death in verse nineteen.
AI summary
Commenting on 1 Chronicles 2:18-24
And the name of the wife of Abishur was Abihail,.... Of the same name was a wife of Rehoboam, a daughter of his grandfather David's eldest brother, Eliab, Ch2 11:18. and she bare him Ahban, and Molid; which are no more mentioned, they perhaps leaving no posterity.
And he took Geshur, and Aram, with the towns of Jair, from them, with Kenath, and the towns thereof, [even] threescore cities. All these [belonged to] the sons of Machir the father of Gilead. (g) That is, the Geshurites and Syrians took the towns from Jair's children.