Searching within Custom Post Types

Hi,

I’ve run into a problem where searching within custom post types just doesn’t work on any of my sites, except for the WooCommerce product post type. It’s the same whether I’m using the browser extension or the WordPress plugin. And yes, all the post types are public and publicly queryable.

I’ve looked everywhere, but I can’t figure out what I’m doing wrong. Maybe you’ve got an idea or can point me in the right direction?

Thanks in advance, Stefan