There may be times that the image or signature do not get laid out properly on a card. It may be a case of Photoshop just misbehaving. Yes, you thought that Photoshop was an inanimate highly tuned program but just take a look at this video to understand just how frustrating the program can be.
Although this video deals with the Calendar Designer actions, the same thing can happen with Greeting Cards and other projects using Photoshop actions.