When Tess is applying gauze to Adam's wound, the close up shot has her wearing latex gloves. As the view switches to a long shot she is not wearing gloves, then as the camera moves in, she is pulling gloves on.
When Willa is talking on the phone to Ben about going to the Fourth of July dance, her cell phone is lit with a blue light. During the conversation, when she says that she has nothing better to do, the blue light is gone. It reappears in the next shot.
When Willa is stripping to get into hot tub with her 2 sisters, she opens her shirt to show a blue gingham print bra. When it is thrown onto the floor it has changed into a pink gingham bra.
As Lily and Jesse are about to step into the river, Jesse's blue jeans are noticeably already wet up to just above the ankles - exactly the height the river is when they finally step into it.
Ben calls Willa to ask her to the dance at Monroe County. There is no Monroe County in Montana. Bozeman is in Gallatin County.