noticed a discrepancy in chenyu vale lore regarding rainjade rite location

i know its old news by now and im not sure if it has been discussed before but i was replaying the chenyu vale world quest "chenyus blessings of sunken jade" and i noticed an ( in my opinion ) important discrepancy which is :

somewhere around the beginning of the quest shortly after we meet little mao and try to locate the rough location of the rainjade together he tells us to go somewhere high up to observe the flow of the river better so that we can roughly estimate where the rainjade might have been carried to by the flow of the water after all these years

the reason why he proposes this idea in the first place is because we had come across a mural previously in which the ancient people were seen standing on an elevated high up place and holding the rainjade as it they were about to throw it down ( other retellings of chenyu vale folk stories also confirm the jade of the rainjade ritual is thrown into the river from a high altitude upstream )

so naturally following the idea of little mao we easily locate where the rainjade is ( its located under the jademouth area ) which also confirms his theory as true but towards the end of the same quest we arrive at the ACTUAL place of the traditional rainjade rite which is around mt laixin

this is the exact part which confuses me bc mt laixin is definitely not upstream on the contrary its downstream especially when compared to where jademouth is located so how come the rainjade piece reached the jademouth area ? did it magically swim upstream or something ? then why did the game up until this point portray it as having been carried downstream from the highest points of chenyu vale instead ???

ugh idk maybe this isnt that important but i feel like its one of those minor details which can completely fuck up immersion and continuity if done wrongly ( which seems like the case here ) esp for those of us who care about lore...

am i maybe missing or misunderstanding something or is this one of those instances where genshin wqs being careless / lazy again ?