Continuity mistake: At the café, no coffee can be seen within at least 1" of the cup's rim while Lisa is standing behind it, but the cup is filled to a high-enough level to be visible after Lisa sits at the table. (01:25:08)
Continuity mistake: The wrapping paper from David's breakfast sandwich transformed with camera shifts, going from almost flat in the front to somewhat curved upward to having an overall bowl-like appearance. (00:20:00)
Continuity mistake: After Diane lit and switched her cigarette to her right hand (and off-camera), most front views of her left arm showed it in front of her, along her stomach, but rear views showed her holding the cigarette in her left hand with her arm more perpendicular to her stomach. Whether her left elbow was fully on the table or over the edge also varied numerous times. (00:08:00)
Other mistake: Tom told David and Lily, "Whoever murdered that girl [Jessica] didn't have sex with her. They used a corn cob." The crime scene photo of the "corn cob" actually showed a partially opened "husk of corn" or "ear of corn." The "cob" is the inner part of the ear beneath the kernels of corn and could more realistically be used to "assault" someone. (00:33:30 - 00:38:30)
Continuity mistake: Lisa's glass was around one-third full. After she took a relatively long drink (leveling the glass to her mouth), the glass was still one-third full when she set it on the bar. Views from the opposite side showed the glass to be fuller, then returned to one-third. (00:55:33 - 00:56:00)