This situation occurs with a lot of quests that have landscape objects that you use. You only have 30 second maybe a few minutes before the item returns to normal and is now available for someone else to use. You will have wander around until you find one of the campfires that you have not used yet. As previously suggested the "Delete" key is a good way to target an available campfire that you have not previously used.
Some quests allow you use the same campfire (object) multiple time. You have enough patience you can stand still wait out the 7 resets.
Unless stated otherwise, all content in this post is My Personal Opinion.