This is probably because in the bbpress plugin there is a template called content-search.php. Many themes also now have a template file called content-search.php. Since the bbPress templates don’t necessarily need to be in a bbPress folder, the bbPress plugin is choosing the template from your theme before the template that is actually in bbPress.
To fix copy content-search.php from the bbPress plugin templates and place it in a child theme in a folder called bbpress.
Functions files and child themes – explained !
So create a directory on your child theme called ‘bbpress’
ie wp-content/themes/%your-theme-name%/bbpress
where %your-theme-name% is the name of your theme
find
wp-content/plugins/bbpress/templates/default/bbpress/content-search.php
Make a copy of this file, and put in in the directory called bbpress that you created above, so you end up with
wp-content/themes/%your-theme-name%/bbpress/content-search.php
bbPress will now use this template instead of the original
