When you use the navstone machine and approach the output where you get the navstones. If you leave the loot screen without picking up the navstone, it will still be gone. This is because all the events are chained to the chest event without checking if the item was removed.
When you use the navstone machine and approach the output where you get the navstones. If you leave the loot screen without picking up the navstone, it will still be gone. This is because all the events are chained to the chest event without checking if the item was removed.
Between event 45 and 46 there should be a condition event with condition type "last event result = 1".