If you are using a different language, the Category names in Knowledge Base are translated correctly in Knowledge Base > View, but not on subpages. See steps to reproduce and screenshots.

1. Log in to a demo instance. 
2. Go to plugins and install a language pack. In this example, we use Italian. 
3. After it loads, log out.
4. Log in as an admin and pick language = Italian below the login box.
5. Navigate to Knowledge Base > Vista (View). You will see a list of Knowledge articles grouped by categories and all category titles are translated to Italian. 
6. Click on one of the categories such as Applicazioni.

Result: This takes you to a kb_home sub-page of the category but it is not translated. Now it is called Applications instead of Applicazioni.

The issue comes from the UI Page kb_home which, instead of gs.getMessage is using the variable from the URL. See line 92 of that UI Page and you can find this: $[jvar_view_topic] > $[jvar_sub_cat].

You can modify the kb_home UI page to fix this issue.

On line 92 of an unmodified kb_home UI Page, you will find this line of code:

$[jvar_view_topic] > $[jvar_sub_cat]

Replace the line of code with the following:

<g2:evaluate var="jvar_topic_display" object="false">
gs.getMessage("${jvar_view_topic}");
</g2:evaluate>
$[jvar_topic_display] &gt; $[jvar_sub_cat]