I had this problem and found that if I make room on either side of the bed, the parent will put the toddler into bed on one side, and then walk around and sit on the other side of the bed to read the story. So I've figured that for some bizarre reason both sides of the bed need to be clear for the whole interaction to work. I used to put the beds against the wall like you have and sometimes it would work and sometimes it wouldn't, but leaving room either side does seem to have fixed the problem (even though its annoying because I like having the beds against the wall).