Missing Media Library page navigation buttons

My Media Library contains many images, so when I view it in List view (/wp-admin/upload.php?mode=list), there should be page navigation buttons in the upper right. Instead, they are absent.

Now when I click to Grid view (/wp-admin/upload.php?mode=grid) and then click back to List view, those page navigation buttons magically appear in the upper right. However, if I click the “next” (>) button to go to a different page of Media Library images, or if I simply refresh the browser, then those page nav buttons disappear again. So those buttons are not persistent.

Any ideas for why this might be?

In case it matters for this issue: The WP Fastest Cache plugin is installed. SSL is not yet activated (so my site is not using HTTPS).