We are aware of an issue where a player may not get their Daily Dungeon Reward occasionally under very specific circumstances, specifically if you were a group of two to enter the "Group Finder" and are matched with another group of two. We are working towards resolving this issue and it will be fixed in an upcoming patch. In the meanwhile, if you experience this issue, please run the dungeon again and make yourself the "Group Leader" to ensure you get your reward.