Revealing mistake: When Ivy is running along the path in the woods, right before she bumps into the wall there are two large tree branches lying in her way. She shortens her steps and hops over both of them, even though her walking stick never touches them and she should have no indication that they're there.
Revealing mistake: There are several scenes in the movie where the shadows of characters can only be created by using spotlights. (i.e. When Lucius and Ivey are walking back to Ivey's house after Lucius has crossed into Covington Woods, look on the left of the screen at the house, you will see the shadow of a chair, and the shadows of Lucius and Ivey. Also, when Ivey is sitting in Covington Woods under her tarp after the two boys have abandoned her, the spotlight is coming from the right of the screen.).
Revealing mistake: In the scene during Ivy's sister's wedding ceremony, right after the people all notice the boys screaming "Mr. Walker, Mr. Walker" Ivy is walking with her arm extended in front of her to find her way through the crowd of rushing people. At one point she has her hand right in front of a man's face (he has a beard and mustache), and despite being blind she then brings it up over his head and behind him in perfect timing without ever touching him. (00:14:15)
Suggested correction: This is because Ivy explains in the movie that people give off a faint color to her. She knew it wasn't Lucius so she avoided him.