The shape of Fern's hair lock covering her right ear is the same when she is at her storage unit in the beginning of the movie as well as at the end of the movie, even though a year has passed. When she is in her vehicle though, arriving at the unit at the end of the movie, there is no hair lock.
The view of Jupiter through the telescope is more like an image taken by Hubble (or at least by an expert photographer who really knows what they're doing) than what you would see with the naked eye, even with what appears to be a 12-inch reflector.
When Fern is talking on the phone, the screen is clearly lit up, even though normally phone screens go black when being held to the ear.
The film is set in 2011-2013, but there is a 2015 edition of Jurassic Park Arcade (2015) in the Wall Drug video arcade.
When Fern receives the message from Swankie containing the video of the swallows, she is watching it on a large iPhone with a 2D interface. This part of the film is set in September 2011, at which time neither this type of iPhone nor that version of iOS had been introduced.
When the Amazon crew is sitting around the table eating and Linda May is introducing them she says "And your good 'ole friend Linda May", however her mouth never moves when she says Linda May.
Swankie says she has the book "Final Exit", by Jack Kevorkian. The book was written by Derek Humphry. Kevorkian is subject of a chapter or two, but did not write any part of the book.
At the Thanksgiving celebration in Mendocino, Dave likens the wineglasses clinking, very clearly, to 'the bells of ACROsanti.' Both his pronunciation and the subtitle spelling agree. He is referring to, however, the bells of ARCOsanti.
The astronomy guy says that Vega is 24 light years away; it is actually 25 light years from Earth.