If it didn't unlock when the mission complete appeared then it won't unlock now. Any error coding/black screen->respawning/contacting server messages etc will invalidate it, even if it doesn't bring you out of the instance. You'll need to unfortunately redo it. [quote]which use bungie APIs[/quote] They're only given access to the post game report about it, they aren't told about why it was invalidated/didn't count.