This is Names of the Fallen, and should be doable at the same time as Securing the Pass (in fact, it is recommended that you do that, as the objectives run in parallel through the cave). It may be that the "Pact Amulet" item that you are trying to pick up has not appeared properly; try leaving the cave and relogging. If that doesn't work, try abandoning Securing the Pass (since you're right at the beginning of it), port to another zone, log off for fifteen minutes, and then try again. This allows the area to do a "soft reset", which may allow the item to spawn properly.

I was having the same problem, until I realized the item the dead pact soldiers were supposed to have was the "Pact Amulet" that another character had already gotten. So, called up the banker, withdrew the amulet, and TADA problem resolved.