The reason why I suggest this is because the anime has shown that Pokemon that evolve by stones often seek them out. For example, an episode of the Sun and Moon series included some Alolan Sandshrew going into a certain cave to look for Ice Stones. The episode where Goh caught a Pikachu included a bunch of Pikachu congregating in one area to dig for Thunder Stones. And Clefairy were shown worshipping a Moon Stone in one of the earliest episodes of the anime. With all that in mind, it makes sense that Pokemon would be drawn to you if you were holding their Evolution stone. Given how a Seadra responded to the Dragon Scale in Pokemon Journeys, this may also apply to items that cause Pokemon to evolve if they are holding them when traded.
The reason why I suggest this is because the anime has shown that Pokemon that evolve by stones often seek them out. For example, an episode of the Sun and Moon series included some Alolan Sandshrew going into a certain cave to look for Ice Stones. The episode where Goh caught a Pikachu included a bunch of Pikachu congregating in one area to dig for Thunder Stones. And Clefairy were shown worshipping a Moon Stone in one of the earliest episodes of the anime. With all that in mind, it makes sense that Pokemon would be drawn to you if you were holding their Evolution stone. Given how a Seadra responded to the Dragon Scale in Pokemon Journeys, this may also apply to items that cause Pokemon to evolve if they are holding them when traded.