Deliberate mistake: When Randy is playing with Agent Rodriguez's gun (after first meeting him), when he accidentally fires it, you can tell the film inexplicably cuts forward a few frames into the same shot, as Randy's body suddenly shifts position and the gun is facing upwards, rather than at an angle as it was the frame before.
Deliberate mistake: During the final montage, we see Erik and Joyce in bed together, and the next sequence is of Teddy talking to his baby brother. This was to show that they got back together and had another kid. The mistake is that Teddy would've been a year older by that time, and so would've looked a little bigger, although there is also the fact that the actor who played Teddy (Dakota Goyo) was between 7 and 8 for the filming. (01:47:30)
Deliberate mistake: During the bathroom scene where Jimmy is trying to get the key to unlock himself from the handcuffs after the little Asian boy had knocked over the garbage can, the toilet paper roll should have had the cardboard tube attached to it upon reaching Jimmy and should not have various pieces of garbage on it.