Just before being arrested James Keene is blending a green smoothie and this can be seen in a full shot of it blending. Seconds later once the FBI has entered, the smoothie is on ground and on his chest however it is yellow, not green.
In correct farm machinery. At Approx. 30+mins in, as Brian Miller (Greg Kinnear) is walking into corn field to view a deceased female, you see a John Deere Combine sitting one row away, yet the corn rows Brian Miller walks through don't have a single ear of corn on them, not even too immature for harvesting. It makes no sense that a combine with harvester implement attached on front would be in that field at that time.
In the close-up of Jessica Roach's corpse at around 30 minutes, her right eye can be seen twitching slightly as the cop removes a strand of hair from her face.
On the 3:22 mark, they show an RCA VHS-DVD combo in November 1996. First DVD players were sold in the United States on March 31, 1997. First combo devices came out in 1999.
At approximately 44:35 you see mating love bugs land on Greg Kinnear's white shirt. These are not found in Indiana/Illinois, where this episode is supposed to take place. They ARE found in Louisiana, where this episode was actually filmed.