Usually the episodes that Kawamoto draw are totally stand alone. Last time he made a "prequel" for the Marshadow movie but that story don't have anything to do with the movie... and Marshadow movie and the manga one are totally different...same for the "prequel" one-shot with Ash... (this one https://pokemon-trainer.com/threads/pokemon-the-movie-20-i-choose-you-manga-adaptation.2046/