When McKenzie regresses to reimagine the scene of her sister's disappearance, she says other children were there. This does not match the opening scene, and is not supported by any other mention of the event.
The private registration on the Range Rover - J04 KAT - is not a permissible UK format [Fake].
Jo has an asthma inhaler, as the audience suddenly discover about an hour into the film when she retrieves it from the Range Rover glove box. No asthmatic would leave an inhaler outdoors overnight in sub-zero temperatures, particularly after the stressful events depicted in the first hour.