Deliberate mistake: In the Extended Cut, when Fujiwara arrives at the mansion, he asks Sook-Hee "So are you carrying out your duties faithfully", then Hideko says "Thank you for introducing her." Later on, when a scene also included in the Extended Cut shows the same scene play a second time, after Fujiwara says "So are you carrying out your duties faithfully" to Sook-Hee, the two share some strange looks that weren't shown the first time. This was done because the moment between them was a scene that was included in the Theatrical Cut, the first time his arrival was shown, but was altered in the Extended Cut to not show this, because their true reason for being at the mansion was not revealed until later and including this brief moment would have given the twist away too early, whereas the Theatrical Cut included a scene that established their intentions much earlier on. The Extended Cut included these brief glances when shown the second time, but still makes for an inconsistency between the two scenes. (00:23:35 - 01:52:00)
Deliberate mistake: When Sook-Hee is first shown her bed chamber, just after Sasaki leaves, she slides open the door to Hideko's room to look inside. After a 5-6 second silence, a thump sound is heard and Sook-Hee quickly closes the door. Later in the movie, when this same scene is shown a second time from Hideko's perspective, the thump sound, which is revealed to be Hideko banging her doll against the wall, occurs 11-12 seconds after Sook-Hee slides the door open. (00:06:38 - 01:32:33)
