Continuity mistake: Allison wakes up with an address in her hand, but when she later shows it to Scanlon, the writing is in a different position on the paper, and the paper does not show the folds it had earlier.
Continuity mistake: At the end when they are confronting Harmony, they pick up the water glass for DNA testing. In the next shot over her shoulder, the glass is still on the table. (00:36:55 - 00:38:09)
Continuity mistake: When Allison wakes up from her dream about the murderer, she runs into the kitchen to write down the car's license place on a notepad: 2TH DOC1. However when she holds it up to show Joe, it's smaller written and not across the notepad as she had originally written it.