Unintentionally funny
I don't want to be too hard on Western actors who have to talk Chinese, but Fiennes's Mandarin was hysterical! Sometimes he sounded like he had lockjaw, while at other times he put the accent on the wrong syllables in the most absurd and incomprehensible ways.
It's probably not his fault. He seems to have a fairly good ear for language. Maybe the director didn't think it was worth the trouble to correct, maybe the accent coach had already left before the scenes were shot, but for people who speak Chinese it just makes you laugh when you're supposed to be paying attention to a serious scene.
And how come one of the Chinese guys at the Shanghai club was speaking Cantonese to the Russian friend of the countess?