Unexpected Blank Space at Bottom of Page Prevents Text Reflow

I have mysterious blank space showing up at the bottom of a page. The text refuses to flow into it. I’ve checked for hidden objects, deleted the page itself, and replaced the text. Nothing I’ve tried fixes it. I’m attaching a screen shot with an arrow pointing to the blank space. I’m working on a Windows machine. It’s throwing off my pagination. 

On a different topic, does any one else find the new requirement to choose a “Category” on this page a pain? There is so much vertical space, and it’s not alphabetized, that it’s frustrating and time consuming.