With the formatting marks revealed: 1) Look for page
breaks or section breaks on page 3, which could prevent
you from deleting that stray paragraph. 2) Select the
paragraph mark, click Format > Paragraph > Line and Page
Breaks and make sure Page Break Before is clear. 3) At
Format > Paragraph >Indents and Spacing make sure that
Space Before and Space After are not excessive for that
last paragraph or for the preceding one on the third
page. 4) If the second to last paragraph mark does not
accompany text, try deleting that one. Alternatively, if
it does accompany text, place the cursor after it and
press Delete. If still no luck, try Backspace (but be
aware that your formatting could change). 5) If all else
fails, select the last paragraph mark, then Format > Font
and check Hidden. 6) I have probably forgotten something.