I did not have the game last year, so this is the first time I've attempted the event, but since the beginning of the Unholy Incursion on PC, I have received no credit for any missions done. I have also not seen any Scourge missions spawn. I see from old posts last year this was a complaint back then as well, though I would have hoped that a year later a special world event would have been patched. If the scourge mission spawn is just very rare, that is fine. But I would at least like credit for the normal missions I've done.