Charrrmed! - S7-E4
Revealing mistake: When Leo is on top of the bridge meditating; the water shown in the background is not moving. Also, cars on the bridge move, but often change speeds rather dramatically (sometimes moving fast and other times moving incredibly slowly).
Carpe Demon - S7-E14
Revealing mistake: After Leo's meeting on the bridge with two of the Elders, it cuts to Phoebe walking down the stairs as she catches Drake dancing, and when he approaches Phoebe to take her hands, the top of the set with lighting can be seen in the dining room.
Carpe Demon - S7-E14
Revealing mistake: When Miss Donovan is chained up, it is very obvious that her hands can easily slip through the shackles.
Chosen answer: Her agent/manager negotiated a special billing as part of her contract. It distinguishes her from the rest of the cast, probably when she became a producer on the show.
JC Fernandez