Audio problem: When Holmwood has the gun pointed in Van Helsing's face in Lucy's crypt, Van Helsing explains about the undead. Switch to a shot behind Helsing and his jaw is still moving even though he has stopped speaking. (01:25:35)
Audio problem: When Dracula and Mina first meet on the street they begin to speak. Dracula's voice has not been dubbed during the first five sentences. Then in mid stream his voice changes from a high pitched regular rehearsal voice to the heavily accented Romanian voice used throughout the rest of the picture. (00:45:20)
Answer: It's unlikely they were falling in love with Harker: they are sadistic, baby-eating monsters who regarded Harker as food and a temporary plaything. As for them sleeping in the open, the local populace dreads and avoids Dracula's castle, so there's hardly any fear of intruders. Van Helsing did enter and kill them, but they reckoned, mistakenly, that he too would be too afraid to do so, especially after their horse-mauling escapades the previous night.