Revealing mistake: The jaguar near the start jumps onto the bar and prowls along it. It knocks over one glass with some force, which shatters, but the second glass is barely tapped by its foot and it smashes to bits too, when it should just have been pushed out of the way.
Revealing mistake: When Jake is sliding on the floor at the mall trying to grab his retainer, streak marks are visible on the floor from where they practised the shot.
Revealing mistake: When Julie is running around the city whilst all the extras are stood frozen, there is a moment where she is walking next to a small park, before beginning to turn right and run down a road. Once she runs onto the sidewalk after running down the road, two girls can be seen stood on the same sidewalk holding hands. The girl on the right can be seen moving her right hand ever so briefly, even though the extras are all supposed to be standing completely still. (00:54:35)
Revealing mistake: Each time Julia lifted the roof window on the camper, it was flush with the roof (like a sun or moon roof). However, two individual shots of that area showed a raised section about a foot high with two windows on one side - totally different from the flat roof window. An aerial view of the roof did not indicate that these were in different areas of the roof. (00:52:20 - 00:55:03)
Revealing mistake: When Archie swung the fire extinguisher in front of the woman, it did not look like the fire extinguisher was close enough to strike the woman's body, let alone knock her out. Also, when Archie came out and closed the door, he would have been walking where the woman's body was on the floor. (00:34:05)
Revealing mistake: The "movie set" steps were so steep they almost looked like they were flat against the wall and the handrail posts were so close together they looked more like vertical blinds. The little dog was able to scale the steps one-by-one, but the larger dog had to leap with effort to get to the top. Also, the baseboards on perpendicular walls (lower right-hand corner of the screen) were not in alignment (off by at least 1"). (01:11:54)
Revealing mistake: When "Snowball" is sleeping on Lena's bed, it is obviously a "stuffed double" (stand-in). Snowball is usually partially hidden behind the dog (so breathing doesn't need to be shown/mimicked). The failure of Snowball to make even a slight movement is a giveaway (e.g, no ear movement when Lena starts talking), but even the stuffed lion, in itself, is not a very good replica - it simply looks fake. (00:33:44 - 00:48:20)
Revealing mistake: Right after baby Estella is born there is no umbilical cord.
Revealing mistake: During one of the chase scenes, an SUV hits a rock barrier and flips over landing on its top. The car spins around, and we see that it is empty. The driver then climbs out as if he was just in the vehicle.
Revealing mistake: After Charlie talks to Emma in Francine's old bedroom and is standing in the doorway, the background (segment of the hallway) is obviously fake. Shown are less than five of the top steps on the staircase, only a fraction of the size of real steps. The lower section of the banister is also a reduced size. (01:31:35)
Revealing mistake: When Alana is walking toward the students, the hedges are mostly dark green, sheared level across the top, and reach to her elbows. Later (after Gary tells Alana he will take a mirror), the hedges turn mostly yellow and flower-like across the top, are quite uneven, and are as high as her shoulders in spots. (Use of a green screen is apparent). (00:00:40 - 00:01:26)
Suggested correction: One look at the scene make it apparent this entry is totally incorrect. The bushes look natural. The yellowness is just colour grading. There is no sign of green screen usage whatsoever. It would make no sense for this film, especially if you realise that director PT Anderson is known to be very much against the use of any sort of VFX or green screening.