I've had this every week for multiple weeks now on my main (who's done the rest of the quest line).
While it does seem a little disappointing that there isn't more story to it (yet!), 1 thing I am happy about is that the souls to be rescued also count for the weekly renown quest (to gather souls).
Also, bonus, unlike the normal souls for the renown quest, these wisp souls DO NOT 'cost' any 'eye of the jailer' points (normal souls count 100 points to your daily 5000 before you have to make a run for it >.< ).
I tend to only do the maw once a week to gather the renown souls and do the weekly quests from venari ... and have begun doing these wisp souls first, as they don't add anything to my eye score (which when you're looking for 15-20 of them, that's 2 whole bars of eye alone, before any kills or objectives etc >.< these cut that down in half!)
I do really hope they add more to this quest line though... and/or just make this a specifically marked 'weekly' quest with some better rewards (some anima would be nice blizz...)
Edit:
Sadly, I didn't receive this quest this week or last (like literally stopped 2 days after writing this... -.- ). Seems it may have been fixed to no longer show up?
Edit2:
Yep, haven't had this quest pop up since writing this... must've been stealth fixed somehow (I didn't see anything in any hotfix regarding it). Ah well, was nice while it lasted...