Character name: Cole Xavier (Level 14 Witchdoctor) Quest: Monkey Barred - open gate (Summer Palace in Monquista - Tierra Primata Skyway). I was attacking the Palace Guard for a key to open the gate with. The Palace Guard approached Ratbeard (Level 11 Bucaneer) without triggering Repel Boarders (he does have Repel Boarders). According to the February 28, 2013 update notes, Repel Boarders is not supposed to fail. What's happening?
It might be that the trigger tile was not empty. If this was the case, then that is by design to prevent weird edge cases like having an opponent be defeated or immobilized in an already occupied tile.