Needless to say, the news that Edward Furlong was returning to the Terminator franchise was a shock for everybody. While we knew that Linda Hamilton would be back in Terminator: Dark Fate, there was no indication of how John Conner would be handled, or if he would even be in the movie. And considering John Conner has been played by several different actors throughout the franchise, there was no reason to believe that, even if John Conner was in the movie, he’d even be played by anybody who had the role previously.
Article source: https://www.cinemablend.com/news/2478367/terminator-2s-edward-furlong-is-really-happy-to-return-for-dark-fate