One Ocean Closer to Destiny - S1-E6
Other mistake: Near the end, Spencer and Alex make love and there is a brief shot of her feet lying on top of his. The scene then cuts to them lying near each other. The problem is, the way Alex is lying would mean her feet would be pointed sideways and unable to appear like they do in that brief shot. She would have to be lying on her back in order for her feet to appear the way they did.