Problem with HOOK_preprocess_breadcrump (Caching?)
Change the cache context from 'url.path' to 'url'

function xxx_preprocess_breadcrumb(&amp;$variables) {
    ...
    $variables['breadcrumb'] = array(
      array(
        'text' =&gt; 'some text',
        'url' =&gt; "/someurl"
      )
    );       
    ...
    $variables['#cache']['contexts'][] = 'url';         
}


I ran into the same problem with Drupal 8.2.4