I've just watched the Shang-Chi and the Legend of the Ten Rings movie, and according to me there's a plot point that is left hanging (possible spoilers if you haven't seen the movie).
Shang-Chi knows where to find his sister Xialing because he received an anonymous postcard with a Macau address.
He assumes that it was sent by Xialing, but when the two meet she is puzzled by the postcard and explains that she didn't send it.
The Wikipedia page of the movie states that the sender was their father Wenwu, but they cite no source, and it makes little sense plot-wise:
Shang received the postcard months before going to Macau, and decided to go only after the bus attack. Why waiting for so long, if Wenwu knew where both pendants were?
Wenwu is trying to retrieve the pendants by force; reuniting Shang and Xialing (both highly skilled in martial arts) would decrease his chances of success.
Wenwu doesn't need his kids' help or approval to go on with his plan. He could have freed his wife from the village before reuniting the family.
Did I miss some part that confirms that Wenwu was the sender? If the postcard is not his, who sent it?