Jack carries firewood to the fireplace, but not kindling. In the next scene he's set up kindling under the logs.
When the pouffe attack Jack, the knife which Su left back in the dead parents' car appears and a wine bottle appears in the woods.
In the shower Su lathers face with body wash but in the next scene it is already washed off.
When Jack and Su rescue the baby from the pickup truck, they're armed with an ax and knife, respectively. Moments earlier Jack was armed with a gun, which mysteriously disappears. EDIT: It's not a gun, it's the handle of the ax. Earlier in the film, they explicitly refused to take the gun, deciding they're not gun people.
When Su reads aloud a text message on her phone, it's addressed to Frances. It's unclear who that is.