When Phoebe and Paige visit Piper in the hospital, she has just finished a meal. However, as she was in labor, she would not have been given food or drink.
When evil Chris and Leo are up on top of the bridge, the background footage of San Francisco is clearly a still image instead of a video. The water is not moving and there is a boat stuck in the same place.
In the parallel world where everything is opposite, Barbas the demon of fear becomes the demon of hope. But the opposite of fear is courage, not hope.