When Gracie and Elizabeth are at the community center making flower arrangements, Elizabeth's flowers have a pair of white Lilies. During the rest of their conversation, her flowers inexplicably are pink Lilies instead.
Natalie Portman uses an inhaler several times and never once uses it correctly. She takes a puff, a short breath, then immediately starts talking. This would result in the medicine ending up in her mouth instead of in her lungs, where it's needed.
Elizabeth (Natalie Portman) uses the iPhone X model which was not launched until 2017, and the movie takes place in 2015.
A sex offender with Gracie's record would likely not be able to attend a high school graduation.
When Gracie and Joe were in the car and she was using her Nebulizer (minute 85), Joe called it a "breathing machine thing" although he's clearly a medical professional and should, as a default, use and acknowledge medical terminology.