I had the same problem. I cooped the story quest with my wife. I chose to progress the story, as we’re doing the same chain. I was killed by the locust swarms after confirming though. The quest reward thing popped up, but I was kicked from the instance. Upon coming outside, I seemed to get no quest reward item. I also doubt I got the xp, as I am now far behind her on xp. On Red Alert is now my next story quest.