Force Anchor ID into page URL
Craft CMS does absolutely nothing to your front end code, and there's literally nothing in Craft that would make anchor links – i.e. &lt;a href="/tabs#anchor1"&gt;Click&lt;/a&gt; – in your front end markup behave in any other way than normal.

The error is probably somewhere in your front end code (either in your Twig/markup or possibly in your JavaScript).