When talking about her last Thanksgiving with Chuck and Ellie, Mary says that it was in 1990. In episode 4.1, however, Mary tucks Chuck into bed in 1993. Also in 3.19, Chuck breaks Mary's favorite necklace in 1991 and Ellie claims that Mary left two days later.
Devon brings Ellie some carrots and remarks how they are rich in Vitamin A. The reality is that carrots contain no Retinol which is a fat soluble vitamin. While carotenoids can be converted into Vitamin A, the process is not efficient.