Checking id is set as down-merge from 5.1-dev (joomla#43880)

Author: muhme

components/com_newsfeeds/src/View/Newsfeed/HtmlView.php

@@ -260,8 +260,9 @@ protected function _prepareDocument()
             $category = Categories::getInstance('Newsfeeds')->get($this->item->catid);
 
             while (
-                (!isset($menu->query['option']) || $menu->query['option'] !== 'com_newsfeeds' || $menu->query['view'] === 'newsfeed'
-                || $id != $category->id) && $category->id > 1
+                isset($category->id) && $category->id > 1
+                && (!isset($menu->query['option']) || $menu->query['option'] !== 'com_newsfeeds' || $menu->query['view'] === 'newsfeed'
+                || $id != $category->id)
             ) {
                 $path[]   = ['title' => $category->title, 'link' => RouteHelper::getCategoryRoute($category->id)];
                 $category = $category->getParent();