I am informed that this is well-known in the UK, probably here too if only I could read the papers, well-known and controversial.
Some Chinese film fans are apparently rather angry about it.
They should be. The additional scenes are pointless. Insulting even. The total screen time for the Chinese stars is about a minute. It's clearly just shoe-horned into the movie with no sense or reason.*
I was told that the dialogue (in Chinese - no English subtitling) was just the doctor saying that they must save Tony Stark (who wasn't noticeably hurt!) because he isn't just an American hero he is a world hero. The nurse gets even less to say or do.
And that's more or less it.
I can understand why Chinese fans feel let down - these are huge stars (or so I'm told) in Chinese cinema.
There is a kind of irony to it too. The studio have gone to great trouble to re-invent the Mandarin. - In the comic books a thoroughly evil oriental - as a western actor hired to pretend to be a generic terrorist. The script has been crafted to turn what was a Chinese supervillain into something else and not offend China but then the additional Chinese scenes have been inserted in such a cack-handed way that it was bound to anger the fans.
And the fans will be even more angry if the rumours on the internet are true and that the scenes they filmed in China but didn't show at all in either country get included on the Blu-Ray release - virtually no one here has Blu-Ray because although many DVDs are labelled "Blu-Ray" none of them actually are. Buying legitimate DVDs is all but impossible and I have yet to see an actual genuine Blu-Ray disc.
If it does get edited and then released in a format that most of the Chinese fans won't be able to watch then that's just piling up the insult.
None of it alters the fact that it's a pretty good movie but it doesn't make Disney/Marvel look good.
(*Apart, of course, from the real world reason that it made marketing and selling the movie in China easier.)