Lucretia Nasin has once more sent me into Miragul's Phylactery. Since her purpose is now clear, I know I should be looking for items related to Miragul's ability to teleport through time, space, and dimensions.
The quest Getting There Before the Coalition is exactly the same as this quest. You will need to click on the book and each of the Spacial Disturbances twice (The Spacial Disturbances re-set after you collect all six, and become clickable again). These are not group updates.
Both powders (the final update) will be awarded at the same time from the loot window.