• I run into this issue frequently; usually it's some tablix/rectangle/textbox that's causing it. One thing I do to identify the offending object is to put different background colors on any object you think may bleed into another page. When you generate as a PDF you'll at least have a color on that extra page which will tell you which object is causing the trouble.

    Another thing I've done is put multiple objects in a rectangle and ensure the "Keep Together on One Page if possible" box is checked in the rectangle's properties.