diff --git a/src/Twig/RelatedExtension.php b/src/Twig/RelatedExtension.php
index b0a98b934..d2bffb3d0 100644
--- a/src/Twig/RelatedExtension.php
+++ b/src/Twig/RelatedExtension.php
@@ -29,12 +29,16 @@ class RelatedExtension extends AbstractExtension
     /** @var ContentHelper */
     private $contentHelper;
 
-    public function __construct(RelationRepository $relationRepository, Config $config, Query $query, ContentHelper $contentHelper)
+    /** @var Notifications */
+    private $notifications;
+
+    public function __construct(RelationRepository $relationRepository, Config $config, Query $query, ContentHelper $contentHelper, Notifications $notifications)
     {
         $this->relationRepository = $relationRepository;
         $this->config = $config;
         $this->query = $query;
         $this->contentHelper = $contentHelper;
+        $this->notifications = $notifications;
     }
 
     /**
@@ -70,6 +74,10 @@ public function getFunctions(): array
      */
     public function getRelatedContentByType(Content $content, bool $bidirectional = true, ?int $limit = null, bool $publishedOnly = true): array
     {
+        if (! $this->checkforContent($content, 'related_by_type')) {
+            return [];
+        }
+
         $relations = $this->relationRepository->findRelations($content, null, $bidirectional, $limit, $publishedOnly);
 
         return (new Collection($relations))
@@ -89,8 +97,12 @@ public function getRelatedContentByType(Content $content, bool $bidirectional =
     /**
      * @return Content[]
      */
-    public function getRelatedContent(Content $content, ?string $name = null, bool $bidirectional = true, ?int $limit = null, bool $publishedOnly = true): array
+    public function getRelatedContent($content, ?string $name = null, bool $bidirectional = true, ?int $limit = null, bool $publishedOnly = true): array
     {
+        if (! $this->checkforContent($content, 'related')) {
+            return [];
+        }
+
         $relations = $this->relationRepository->findRelations($content, $name, $bidirectional, $limit, $publishedOnly);
 
         return (new Collection($relations))
@@ -101,8 +113,12 @@ public function getRelatedContent(Content $content, ?string $name = null, bool $
             ->toArray();
     }
 
-    public function getFirstRelatedContent(Content $content, ?string $name = null, bool $bidirectional = true, bool $publishedOnly = true): ?Content
+    public function getFirstRelatedContent($content, ?string $name = null, bool $bidirectional = true, bool $publishedOnly = true): ?Content
     {
+        if (! $this->checkforContent($content, 'related_first')) {
+            return null;
+        }
+
         $relation = $this->relationRepository->findFirstRelation($content, $name, $bidirectional, $publishedOnly);
 
         if ($relation === null) {
@@ -164,6 +180,10 @@ public function getRelatedOptions(string $contentTypeSlug, ?string $order = null
 
     public function getRelatedValues(Content $source, string $contentType): Collection
     {
+        if (! $this->checkforContent($source, 'related_values')) {
+            return new Collection([]);
+        }
+
         if ($source->getId() === null) {
             return new Collection([]);
         }
@@ -179,4 +199,18 @@ public function getRelatedValues(Content $source, string $contentType): Collecti
 
         return new Collection($values);
     }
+
+    private function checkforContent($content, string $keyword): bool
+    {
+        if (! $content instanceof Content) {
+            $this->notifications->warning(
+                'Incorrect usage of `' . $keyword . '`-filter or function',
+                'The `' . $keyword . '`-filter or function can only be applied to a single Record.'
+            );
+
+            return false;
+        }
+
+        return true;
+    }
 }
diff --git a/templates/_partials/notification.html.twig b/templates/_partials/notification.html.twig
index 00fb21bf6..fba7a5514 100644
--- a/templates/_partials/notification.html.twig
+++ b/templates/_partials/notification.html.twig
@@ -94,14 +94,16 @@
     <h1> {{ subject|markdown|striptags('<em><i><code>')|raw }}</h1>
     {{ body|markdown|raw }}
     <ul>
-    {% for frame in backtrace|slice(2) %}
-        <li>
-            <code>{%- if frame.type|default() is not empty -%}
+        {% for frame in backtrace|slice(2) %}
+            <li>
+                <code>{%- if frame.type|default() is not empty -%}
                     <abbr title="{{ frame.class }}">
-                    {{- frame.class|split('\\')|last()|excerpt(24) -}}</abbr>{{- frame.type -}}
-            {%- endif -%}
-            <strong>{{- frame.function -}}()</strong></code>{% if frame.line|default() %} - line {{ frame.line }}{% endif %}
+                        {{- frame.class|split('\\')|last()|excerpt(24) -}}</abbr>{{- frame.type -}}
+                    {%- endif -%}
+                    <strong>{{- frame.function -}}()</strong>
+                </code>{% if prevline|default() %} - line {{ prevline }}{% endif %}
+                {% set prevline = frame.line|default() %}
             </li>
-    {% endfor %}
+        {% endfor %}
     </ul>
 </div>