I have a 100 page document. This bizarre occurrence has happened twice in the
document. In both instances, it occurred when I went to apply a heading
format at the beginning of a new chapter. In each case, the change was made,
but in one location, 35 blank pages were added in front of the heading, and
in the other, 12 blank pages were added.

What I've looked at so far. In the first instance, the previous chapter
ended with a figure/caption. Deleting the caption and subsequent section
break brought the next chapter heading back to the next page. Adding a new
caption and section break did not prevent the same effect from happening when
I tried to reestablish the new chapter heading.

While the caption and break are on the page, I moved the cursor to the
right. When I got to the end of the caption's line and the paragraph mark,
the cursor disappeared rather than go to the next line. The top ruler changed
to what looked like column settings, as if a table were there. Another time,
the top ruler went away completely.

I certainly didn't add a table. Can anyone help me with this one?