First of all, the Tabard of the Victor requires Level 80, which was our first clue that it was probably not meant for pre-Wrath eyes. The tabard binds on pick-up, provides 250 Armor, +20 Stamina, +10 to All Resistances. Upon equipping it, your resilience rating improves by 15 and it increases movement speed and life regeneration rate. The funniest part -- and what makes me think this could be a prank by our dear game designers -- is the tabard's use is described as: "Use: Show how heroic you are! (55 Secs Cooldown)" and the bottom line description is, "The Mark of a True Hero." It seems that perhaps the glitch was caused by an error in the cache because when it was cleared the tabard's description correctly matched the Summer Flames tabard.
[Thanks, Jagoex and James Vertovec!]