[SOLVED] Navigation missing

I've already solved this problem, but I'm posting it in case anybody else runs into this. I've been using this theme for a number of years (love it, by the way), but just updated to the latest version for a new website I'm building. I had written five posts, but kept them in draft. When I was ready to publish them, I did it in bulk, i.e., I published all five of them with one button click.

Then I noticed that the navigation bar was not appearing for these first five (and only) posts, so I thought something was wrong with the theme. I finally figured out that because I published all five posts simultaneously, they all had the exact same timestamp. When I went back and changed the timestamps so that they were all different, the navigation worked fine. Duh.

Hopefully this will save somebody the two hours I lost.