When Sophia enters the dining room right after the fake murder, the birthday candles go out between shots without anyone extinguishing them. A single one keeps going out and then lighting again.
The cut throat of the Murder Mystery actress portraying "Candy" has one gash/slit throughout most of her scenes. This makes sense, as her throat was said to only be slit once. (It resembled a cleanly cut "Colombian Necktie".)
In her final two scenes, however, her wound is shown as two gashes/slits.