WoWDB

It seems that as of a couple beta builds ago, learning and adding Glorious Standard of the Sunreaver Onslaught to the Toy Box will also add  Glorious Standard of the Kirin Tor Offensive to the Toy Box.

I believe this is intended - and not a bug - because of two reasons:  Faction-changing the character that has the standard in their inventory will also cause the standard to change to its opposite faction, too.  Also, the Toy Box is account-wide, so it'd be a bit silly not to recognize that many players' World of Warcraft accounts have characters of both factions.