After the tourists enter the castle, the coach drives away and the gate shuts. Charles runs towards it, while the others stand in the foreground, to his left. When he walks back, the camera cuts to a slightly different angle. Diana, Helen, and Alan are now standing further to the right.
When Dracula opens his shirt for Diana Kent to taste the blood on his chest, he is interrupted and has to leave by kicking open a door. He picks Diana up and takes her to a horse carriage, and in the very next shot, Dracula's shirt is closed, completely buttoned back up. He couldn't have done this while carrying Diana's body.
This story takes place ten years after the end of "Horror Of Dracula". It is supposedly the same castle that all the natives fear, yet the castle looks completely different on the outside as well as the inside.