Steve,
Because you have a combination of regular and automatic connector lines that behavior can occur. I adjusted your diagram and it should be looking better (see the attached). I basically had to adjust a few things on the right side after expanding the main split at the top which can be made wider by going to the "Internet Cable Service Modem" shape and where the line links to the shape, click the line and you will see 2 control points where you can adjust the width.
Regards,
SmartDraw Support