From the incomparable Jan Berinstein, a Word power user and then some! Thanks Jan!
I just had this problem yesterday. I was revising a document where I had previously inserted a section break to separate a landscape orientation table from the rest of my text, which was in standard portrait orientation. I deleted the table, but ended up with a blank page that wouldn’t go away. Every time I attempted to delete the unneeded section break, it reformatted my entire document. Argh!
Issues like this are why you should buy Jan’s new book: Formatting Legal Documents with Microsoft Word 2016, available on Amazon. Here is Jan’s post:
Over the past few years, my clients have frequently reported difficulty deleting an extra page that appears at the end of a document – typically a pleading. Sometimes the problem involves a table (whether an actual columnar table containing data or a single-cell table used for a signature block) that falls at the end of […]
https://compusavvy.wordpress.com/2016/02/24/tiplet-deleting-an-extra-page-word/
Oregon Law Practice Management 
So glad that my post was helpful to you (I can’t believe the coincidental timing!). The problem arises with surprising frequency, but the solution isn’t intuitive in the least.
Deleting section breaks can be frustrating, as well – as you know from experience. Because each section break contains page formatting codes for the section that precedes it, deleting a section break results in formatting changes (the page formatting instructions contained in the *next* section break are applied). Again, not intuitive.
Hoping to write another new post soon. Meanwhile, I appreciate your letting folks know about my book(s)!
Yeppers. That be the problem and such. 🙂