Various frequencies

I am tracking links, they are displaying PDFs within the browser, like ( a tags omitted):

class=“btn btn-primary matomo_download” href=“https://xxx/article/view/5080/3291”>PDF

The clicks are shown in Matomo under Behaviour as Pages and, because of the “matomo_download” class, as downloads as well. In general, there are less downloads then PageViews; when checking the numbers of the Page Titles I find different frequencies too.

Why do these frequencies differ? Has anyone an idea why they are not the same?

Thank you for any hints.