Other mistake: When Margaret and Andrew first walk into the Immigration Office there are a group of extras seated directly to the left of them, in two rows. One of them, a guy with glasses and long black hair, wearing a white shirt with patterns (back row, second from the wall, next to the guy in the light yellow shirt), briefly looks at the camera as Margaret and Andrew walk by.
Other mistake: When Andrew and Margaret leave the immigration office, and they are standing outside talking, there is a short woman in a light green sweater that walks behind Margaret, repeatedly - either the backdrop is a greenscreen on a loop or they just had the extra making rounds behind the couple.
Other mistake: When Margaret is hoisted from the water, her clothes should have been sopping wet, but they looked like they had partially dried over the course of several takes.
Other mistake: Grammy says she was knocked up when she wore the wedding dress in 1929. She is celebrating her 90th birthday. That would have made her about 10, since the movie was made in 2009.
Suggested correction: She said her mother made the dress by hand in 1929. Then when the fit was too big, she said she was chesty and was pregnant at the time she wore the dress. But nothing about her wearing the dress in 1929.
Suggested correction: Grammy's mother was the first person to wear the dress in 1929 - she was the one who married the Russian.