SWTOR: Why is Tulak Hord's ghost on Yavin 4?

Dude's tomb is on Korriban, so how is he on Yavin IV? To quote someone from swtor.com: 


Additionally, the appearance of the Force ghosts on Yavin 4 is questionable - Ragnos is buried on Korriban, Hord's remains were last seen on Hoth, Kun has bound himself to a temple on Yavin and Sadow's tomb was locked by the Emperor's agents

Apparently they were all stationed on Yavin IV already, and their "convergence" of energies rose up the Ancient Threat entity: "Long-forgotten Sith spirits have awakened on Yavin 4. This convergence of dark side energies could give rise to a powerful and ancient threat within the moon's already-treacherous jungles..."

Perhaps the return of the Sith to Korriban awoke Naga Sadow's spirit and he fled to Yavin IV. Hord's spirit might have ended up on Yavin IV originally. Kun's is kinda irreconcilable, but maybe he's projecting a portion of his essence to help out.

I don't know, seems very suspect from a lore respect. Hord's tomb is on Korriban and his remains were last on Hoth, I'm not sure why he'd be on Yavin IV.

Revan’s raw power dragged his spirit to Yavin.

Spirits can teleport to locations with dark side energy that they have visited previously. Despite being buried on Korriban, Ragnos's spirit appeared on Cinnagar when Kun and Qel-Droma's amulets reacted to each other.