Although I am sure we can attribute the damage to both pylons to the reckless centaur stomping about, I suspect the timing of their rampage resulted in the shards being separated. I know little about their quarrels, but I do know there are at least two main factions that have trespassed into Shen'dralas: the ferocious Magram and the cunning Gelkis. Keeping these treasures in the midst of a battlefield would be unwise. By now, I am assuming they have taken their trophies back to their own villages.