"We've Confirmed 4K For Playstation 4 Pro. Have Not Made Any Promises About Scorpio As Of Yet."
https://www.youtube.com/watch?v=58XtTJJ2mF4&t=14m30s
SInce the PS4 Pro can run it at 4K the Xbox One X definitly should run it at 4K. If its not 4K then something fishy is going on.