In Chihuahua Mexico, the worker says he's earning $2 per hour. But in Mexico, their currency is pesos. When their coupon hack started in 2012, the equivalent would be about 27 pesos per hour.
The postal inspector tells Connie it's 1 year for every $100,000 earned fraudulently and that she's looking at 40 years. In a later scene, another postal service worker says they stole 40 million in counterfeit coupons. $100,000 x 40 is 4 million not 40 million. (Edit: The inspector actually says 40 to life, which would be correct since 400 years would be to life)
The logo and font for the United States Postal Service are incorrect. The correct font is a stylized italicized blue front with the words United States on top and Postal Service on the bottom, with a red line between the top and bottom, and the correct logo is an eagle's head; the type in the film has the words in a more generic font, and uses a star logo rather than the eagle's head. This change was most likely made for copyright reasons/inability to secure the rights to use the actual logo/etc.
The General Mills coupon says "Cash redemption value: 1/20 of All Right Reserved." It was probably supposed to say "value: 1/20 of one cent" or similar.
The first Lamborghini Urus was released in 2017, however the movie has them purchasing them in 2012.
The gentleman at the gun counter quotes the John Wick movies as an ad for guns. However, the coupon hack started in 2012, which is 2 years before the John Wick movies came out.