Ubisoft has apologised for using a historical re-enactment group's flag in Assassin's Creed Shadows concept art and the physical artbook that comes bundled with the Collector's Edition.
As reported by Siliconera, the flag belongs to a historical re-enactment group called the Sekigara Teppo-tai (or Sekigahara gun group, thanks VGC). In a post on X, Ubisoft Japan said that the art in question will not be used or distributed further beyond this date, except for the aforementioned artbook, and apologised for the inclusion.
As ever, we are astounded at the eagle-eyed nature of observers online. Below, we've included an image of the Teppo-tai in action and one of two instances of the flag used in Assassin's Creed Shadows concept art. Strain your own eyes, and see if you can pick out the offending banner: