I found an answer to my own question, but it is probably not the best; I simply copied the info with the box around it, and reprinted it in the same document. The reprint came out just fine, with no box around it. Then I deleted the item with the box, and I am back to normal. Perhaps sooner or later someone will figure why something gets boxed in when it is e-mailed? Or better yet, how to e-mail something written in LibreOffice Writer without generating a box in the first place?
08/20/17 I found a better answer, and thought I should share it. If you e-mail a LibreOffice document to yourself at another computer, you can copy it from the e-mail and paste it in a LibreOffice Writer document, but it will be formatted with separate paragraphs around each sentence. If this happens to you, simply go to “Edit” and “Select All”, again in “Edit” open “Paste Special” and “unformatted text” should be highlighted, hit “OK”, and the paragraph lines (boxes) should go way.