All the Primeval Obelisks are empty

[zerotje]

I have been in four quests with empty Primeval Obelisks. No runes.

[Dredi]

The ones I've encountered seem fine. If these are commonly done lower level quests its possible that they havent respawned from the last person.

[Bacon_Cheese_Burger]

This happens often in lowlvl quests.

[Mushroom Mushroom]

They respawn on a timer. So, every 10-15 minutes, they reappear.

[Astegard]

This just means someone did the quest just before you and took all the runes.
They are indeed on a refresh timer.