If you note bullet two in Siffow's list of known issues, some DLC 1 (The Dark Below) and DLC 2 (House of Wolves) cards, including missions and enemy cards, are not properly unlocking. When a bug is corrected, Siffow generally updates the thread by removing/clarifying the corresponding known issue in the list. Since the list item is not explicit about which particular cards still have issues, I cannot tell you if your particular cards of interest have been fixed. I think it is safe to suggest waiting until this item is removed or further clarified by Siffow before finishing the House of Wolves abandoned quest on your last character.