There are two kinds of miracle events which the game never really explains to you. The first is one triggered in the world by a certain quest or trigger being hit, an npc then walks up to a random person and either gives/sells you an item. The second is that they walk up to you and give you nothing, but tell you about a miracle event that is triggered by finding an item in the world and giving it to them. The problem with number 2, is that these conversations are usually poorly translating or misleading, so you end up angry thinking that the random event is bugged. If you get a random encounter from feng si, she will give you nothing. Instead, she will tell you about the world item that she wants which will give you a reward. The item she wants is the bird egg, and this egg spawns in 2 of the trees above her. If you are the person to loot this egg and hand it to her, you get a tradable book of speed up without trace. Most of the time this egg is camped by a low level bot which can not be harmed. You do not have to be friends with feng si if you want the tradable script. All you have to do is camp the trees for 1-72 hours and wait for the egg to spawn.
But if you want the untradable script, then you need to go to the guy who eats medicine.
Since people get confused about this, I will explain some more. There are actually other miracle encounters like this in suzhou, and I imagine throughout the world.
For example, there is a box that spawns on the tower in the town in front of the oil boss at 620, 530. if you get it he will give you a brocade box with a silver grade recipe in it. There is another box at 625 1130 ontop of the sign post which you can give to the girl to get a box with another silver recipe in it. And there is a bird nest in a tree at 847 1434 which contains a hairpin which you can exchange to the npc under the tree for another box with a different silver grade recipe in it.
The game doesnt seem to tell you about these but it tries to. Once you understand how it works, the gossips npcs say start to make sense. For example, there is a gossip relating to the oil boss being upset about something. He wont tell you what he is mad about, UNLESS you get him to spawn on you as a random encounter. THEN he will tell you that he is mad because someone put his box on top of the pagoda in front of him which gives you the clue to go climb the pagoda and get the box. Problem is, if someone already got the box, you will climb the pagoda and there will be nothing there and you will think "god dammit snail, another retarded translation". And if you have the box item on you when you go to visit him, he will have a red lantern over his head and again give you the same text explaining the situation which is kind of a useless hint after the fact. Random encounters are typically triggered by people turning in the quest.
So the order that the game wants you to do is, talk npc, collect the gossip that says the oil boss is upset, then you go to the oil boss and do his quest/give him gifts so he likes you, and then one day when you turn in his quest you will personally trigger the random encounter where he explains to you in role playing terms that a box spawns on top of the tower in front of him and he wants you to get it for him some day so he will then give you your prize.
Simarily, the game gives you a gossip about feng si that he likes eggs. You think 'lol wut', then you hang around feng si and get his friendship up, one day he spawns a re on you and tells you about the eggs in the trees, then you go and check the trees everyday until you see one spawn, snag it, and turn it in for speedup without trace.
Or you can just skip the whole thing, look at a guide online, and grab the item and turn it in while everyone else dicks around with the really time consuming re system.