Does Mirkwood Explorer lose progress placed on him as a result of a card like Fallen Stones? I assume yes from a strict perspective, but if we go by designer's intent, it is possible they only intended for it to remove progress from quest cards/locations.
Response : After Mirkwood Explorer quests successfully, place 1 progress on it.
When Revealed: The first player (choose 1): removes all progress tokens from play, or reveals 2 cards from the encounter deck and adds them to the staging area.