In general, if you turn in items to an npc to initiate a spawn or some other event, and then fail to complete that part, do you lose all your turn-ins? If a turn-in provides an item, is that item able to re-initiate the process?
There was a general fix a long time ago to quests so that NPC's wouldn't eat turn ins if you were not at the right step (including pets), but theres a 1% chance something was missed. If its a spawned or triggered event, unless they specifically scripted a reset or something to return the items, then they are gone and you have to re-farm. Old events are more than likely going to require you to re-farm the items.
