Came back to this thread because I knew there was an "iron crosses won't fill up" thread, and something similar just happened to me.
After torpedoing a lone merchant, making a daring attack on Methil, and then gunning down/torpedoing another lone merchant, I got a "Completed" window. Fine, I think, although, wow, wasn't expecting it nearly that early, must've been one heavy tanker. Oh well, no complaining from me!
Except... no promotion points, and no iron cross.
It turned out that it wasn't the Mission I had accomplished, it was BDU's stupid "reposition here and continue your patrol" order that I had received while on patrol before my harbour raid
.
And yes, unlike certain others, I did buy the game
.