Just handed in another "Report to Captain Ironfist" and then got the quest "War Banners" from him.
As soon as I got that, a new quest popped up on the map:
Valstag Ironjaw
[28] Report to Captain Ironfist.

But Ironfist hasn't got any more quests at this time (I'm level 23 currently).

EDIT: After a relog the quest marker disappeared.