Libby and Sarah have been coming to the cottage since they were children, but Sarah tells Mr. Beckwith that her aunt built the cottage 50 years ago, which would mean that Libby and Sarah were actually in their late 20s-early 30s when it was built.
When Joshua passes by Libby to enter in the house, Libby is sitting with a window behind on her right-hand side. In the shot from inside, Libby appears with the window in her back, a little more to her left side. Later, when Sarah and Tisha come back from the sea side, there is no window behind Libby at all.
When Libby takes her souvenirs box from the vanity drawer, she picks up the box with her right hand and closes the drawer with the left one. In the following shot she is holding the box with her left hand.
When the radio (or wireless) is switched on in order for Libby to listen to her favourite programme, the sound of the broadcast is heard immediately as though it were a modern transistor or digital radio. But the film is set in the mid-1950s during the era of valve wireless receivers (see also the prop used in the scene), meaning that the ladies would have to wait for several seconds while the set warms up before the programme could be heard.
When Sarah and Mr. Maranov go onto the porch to look at the moon, there is a yellow, moon-like orb in the sky behind him, although the moon, judging from the light, is in front of them. Moreover, the sky behind Mr. Maranov is pitch black while the sky off the ocean is light.