When Cal is at the hardware store trying to find the author to the Santeria book, the guy that refuses to talk to him turns off the lights and immediately disappears, despite the fact that there is still enough light that you should have seen him there or at least walking out of frame.
When Jessica and Cal are participating in the Santeria ceremony, Jessica is sprayed with chicken blood. The blood initially hits the edge of her shirt near her neck. In a following shot, that part of her shirt is completely clean.