If grouped, only 1 person can gather the two jars, and there is a 36-hr zone reset timer. Picking up the jars will "bug" if you inadvertently pick up just 1 jar. *Update 25-Dec-2016, There is now only a 90 Minute lockout timer.*
The jars appear to be linked, and both can be picked up with a single click.
Steps[]
Locate and enter the Down Below. The nearest entrance is behind the In Range archery shop in Elddar Grove. ( 518, -17, -397 ) Copy/waypoint 518, -17, -397
Seek out the place where the Bloodsabers are congregating. ( 8, 0, -122 ) Copy/waypoint 8, 0, -122
Search the Bloodsaber hideout to locate a Curious Entrance and venture within. ( -5, -3, -143 ) Copy/waypoint -5, -3, -143