Menu disappears when linking to categories

This might not be a Roots-issue, but maybe some of you people know what might be wrong:

I have a menu, with one regular page (with a submenu), and three links to different category archives. When clicking the regular page menu-item, the menu behaves as it should, but if I click one of the categories, the menu disappears.

The HTML output is like this (when I click on one of the category menu-items).

<nav class="collapse navbar-collapse" role="navigation">

The wp_debug tells me nothing about whats going on.

Any ideas?

Can’t reproduce this. Try disabling all plugins and trying again, if you have not already.

Any customizations to the the main $query using pre_get_posts? Other modifications from the base theme you can try disabling to narrow down what the issue is?