Is there any reason why Jirachi is locked from being shiny in ADV/DPP/BW when it can be obtained as such through the Colosseum Bonus disc?
https://screenrant.com/pokemon-shiny-hunt-jirachi/
https://projectpokemon.org/home/files/file/1696-wishmkr-shiny-jirachi/
https://projectpokemon.org/home/files/file/1696-wishmkr-shiny-jirachi/