Other mistake: Harry is typing on the keyboard, then reading off the computer screen what he writes. When the screen is shown, it appears to be off and, therefore, no print is visible. There is a reflection of light in the upper lefthand corner. (00:21:45 - 00:22:28)
Continuity mistake: The outside chairs are angled differently and there is more space between them when Hector the dog is running up to the chairs than after he and Harry sit. When Harry gets up and walks away, the chairs are spaced apart again. (00:19:40)
Continuity mistake: Harry sets his pen off the left side of his notepad and has both of his hands to the right of it, but the pen is on top of the notepad when the camera shifts. (00:06:40)