Redirect /author to /profile fails and goes to shopsite

Hello,

I want to use this plugin to show post authors information.
The posts are used for custom entries which users can create on a restricted subsite.
When clicking on the post authors name, it goes to /author/nickname but I want it to go to the plugins url which is /profile/nickname.

Therefore, I have written some code into my child theme’s functions.php:

//redirect /author to /profile
function author_redirect() {

  $url = urldecode($_SERVER['REQUEST_URI']);

		if( strpos($url, '/author/' ) !== false) {
      $profile = substr($url, strrpos($url, '/') + 1);
			wp_redirect( site_url( '/profile/' . $profile), 301 );
			exit();
		}
}

add_action('template_redirect', 'author_redirect');

That works if the user isn’t existing, e.g. /author/example redirects to /profile/example
If the user exists though, it redirects to the shop (woocommerce) site.
I looked through a lot of plugins (wpseo, wp security, wpml, woocommerce etc) but I can’t get it to work.
Do you know any workaround? I didn’t find a setting in wp user manager to redirect correctly.

Thanks in advance
arunha