I've never actually had this come up, but I was thinking today about what would happen if you played a card that interacted with an encounter card that is immune to player card effects while the card is either in the encounter deck or in the encounter discard pile. Most of these immune cards are never actually in the encounter deck because they are put into play or kept out of play at the start of the quest, but there are a few locations that are in the encounter. For example with Out of the Wild; Could you remove the location from the game, or is it immune? Can you use Shadows of the Past to put the location back on the deck?
I'm guessing the answer is that you ignore the text on the card unless it is in play, but I'm not sure. I recall a similar ruling that said you can use Fortune or Fate to bring Beorn back into play. Has anyone resolved this before?