Why was "their brother" not mentioned before the name of Shuʿayb (peace be upon him) in Surat Ash-Shuʿara, unlike what was mentioned with the other prophets?

Some exegetes mentioned that Shu'aib (peace be upon him) was sent to the people of Madyan and the People of the Aika, and that he was from the people of Madyan. Therefore, Allah attributed him to the people of Madyan by saying: "And to Madyan [We sent] their brother Shu'aib." As for when the People of the Aika were mentioned, "their brother" was not said. It was said that the People of the Aika are the people of Madyan, and the reason for not mentioning their brotherhood to Shu'aib when mentioning the Aika is to clear Shu'aib from being attributed to it.