When Catherine is testing for PCP, she puts the piece of the plant in the bag and cracks it and shakes it. The blue square inside the bag changes in between shots. It's at the bottom in one shot, then in the next, it's in the top of the bag.
When Grissom is investigating Hodges' "death", Hodges states that the pager used in the zip gun is a pre-1990s pager that does not have a display for a call back number, but during the replay of how the zip gun works, the pager shown has a display and a Las Vegas area code number is shown on the display.
When the gang is playing the Second Murder Game, they say that Henry was trapped in the freezer with many bottles of chemicals including Methyl-Ethyl-Ketone. When they are guessing the chemicals that were in his system that may have killed him they guess Methyl-Ethyl-Ether.