At the start, when the woman gets stabbed by the man, she's clearly stabbed in the lower part of her abdomen. The next shot, however, the wound is in her chest.
At 11:11 Prentiss, Morgan, and Hotchner are at the house recreating the steps of the real estate woman's death. Morgan says the killer closed the door before stabbing his victim, but he did not close the door until after he stabbed her. Morgan then says the killer dragged the woman to the couch, when, in fact, he just followed her over to the couch then made her sit down.
Morgan and Hotch both state that the unsub chose an open house, for guaranteed privacy and no fear of interruption. A real estate open house is an opportunity for the realtor to drum up business on a property by allowing potential buyers to just drop in without appointment.
Garcia points out that the footage of Vincent's mother's death is analog and has been digitized. She also says that the footage is seriously degraded. Whenever we see the tape being played (or the ripped version of it), we occasionally see a few horizontal degradation lines appear on the screen for a few frames and they are completely still. The only consumer camcorder formats available at the time were Betamax and VHS-C (and 1983 was the first year they were introduced). For analog tape formats like this, degradation lines would be moving downward. What is shown on the TV looks more like the loss of part of a signal from a TV broadcast.
At the beginning, a very tall palm tree can be seen reflected in the window of the vehicle driven by Vincent (Alex O'Loughlin). The case is set in Buffalo, New York, where the freezing winters would make it impossible to grow a palm tree, let alone one of that height.
Several times during outdoor scenes, high dark gray mountains can be seen in the distance. In the vicinity of Buffalo, New York there are no mountains similar to those visible in those shots, revealing that this is, of course, actually filmed in Los Angeles.