In the introduction, Suburbicon is described as having a shopping mall. In the 1950s, they were called "shopping centers." The use of the British term "mall" in this sense did not begin to take hold in America until the mid-60s.
The term Mall is only really used in North America and is not a British term. Malls are called shopping centres or shopping precincts in Britain.
Margaret turns off the TV using a Zenith Flash-Matic, the first wireless TV remote control. It was basically a flashlight with a very narrow beam. You aimed it and one of the four corners of the TV console to trigger a function. The TV turns off when she hits the lower right corner. This corner is for the mute volume function, not power off.
When Hightower visits Gardner in his office he is addressed wrongly as 'Lieutenant' multiple times although his Captain's bars are clearly visible and he was addressed with his correct rank in their first encounter earlier in the movie.
Incorrectly Labeled as Goof: Nicky grabs the telephone and locks himself in the room. He's disconnected when the cord is pulled out. Later, Mitch uses the phone to try and call the police.
Mitch was gravely injured and was not aware that the phone line had been pulled out. As he was dying he tried to make a call, but the phone didn't work. As he was dying and becoming incoherent he tried to talk to a dead phone.