diff --git a/webapp/src/Controller/Jury/ShadowDifferencesController.php b/webapp/src/Controller/Jury/ShadowDifferencesController.php
index f8e1e64128..576c4cbfb3 100644
--- a/webapp/src/Controller/Jury/ShadowDifferencesController.php
+++ b/webapp/src/Controller/Jury/ShadowDifferencesController.php
@@ -104,6 +104,7 @@ public function indexAction(
             ->select('s', 'ej', 'j')
             ->andWhere('s.contest = :contest')
             ->andWhere('s.externalid IS NOT NULL')
+            ->andWhere('s.expected_results IS NULL')
             ->setParameter('contest', $contest)
             ->getQuery()
             ->getResult();
diff --git a/webapp/src/Service/ExternalContestSourceService.php b/webapp/src/Service/ExternalContestSourceService.php
index 3d0212d523..bad3824ab9 100644
--- a/webapp/src/Service/ExternalContestSourceService.php
+++ b/webapp/src/Service/ExternalContestSourceService.php
@@ -50,6 +50,8 @@
 use Symfony\Component\PropertyAccess\Exception\UnexpectedTypeException;
 use Symfony\Component\PropertyAccess\Exception\UninitializedPropertyException;
 use Symfony\Component\PropertyAccess\PropertyAccess;
+use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 use Symfony\Component\Serializer\SerializerInterface;
 use Symfony\Contracts\HttpClient\Exception\DecodingExceptionInterface;
 use Symfony\Contracts\HttpClient\Exception\HttpExceptionInterface;
@@ -107,7 +109,7 @@ public function __construct(
         protected readonly EventLogService $eventLog,
         protected readonly SubmissionService $submissionService,
         protected readonly ScoreboardService $scoreboardService,
-        protected readonly SerializerInterface $serializer,
+        protected readonly SerializerInterface&DenormalizerInterface&NormalizerInterface $serializer,
         #[Autowire('%domjudge.version%')]
         string $domjudgeVersion
     ) {
@@ -1886,7 +1888,8 @@ protected function addPendingEvent(string $type, string|int $id, Event $event, C
             objectId: $id,
             data: [$data],
         );
-        $dependencies[$type . '-' . $id] = ['type' => $type, 'id' => $id, 'event' => $event];
+        $normalizedEvent = $this->serializer->normalize($event, Event::class, ['api_version' => $this->getApiVersion()]);
+        $dependencies[$type . '-' . $id] = ['type' => $type, 'id' => $id, 'event' => $normalizedEvent];
         $this->addOrUpdateWarning($event, $data->id, ExternalSourceWarning::TYPE_DEPENDENCY_MISSING, [
             'dependencies' => $dependencies,
         ]);
@@ -1917,7 +1920,7 @@ protected function loadPendingEvents(): void
 
                 $type  = $dependency['type'];
                 $id    = $dependency['id'];
-                $event = $dependency['event'];
+                $event = $this->serializer->denormalize($dependency['event'], Event::class, 'json', ['api_version' => $this->getApiVersion()]);
 
                 if (!isset($this->pendingEvents[$type][$id])) {
                     $this->pendingEvents[$type][$id] = [];
diff --git a/webapp/src/Service/SubmissionService.php b/webapp/src/Service/SubmissionService.php
index b800049a1a..e6f63205b5 100644
--- a/webapp/src/Service/SubmissionService.php
+++ b/webapp/src/Service/SubmissionService.php
@@ -89,7 +89,9 @@ public function getSubmissionList(
         }
 
         if ($restrictions->withExternalId ?? false) {
-            $queryBuilder->andWhere('s.externalid IS NOT NULL');
+            $queryBuilder
+                ->andWhere('s.externalid IS NOT NULL')
+                ->andWhere('s.expected_results IS NULL');
         }
 
         if (isset($restrictions->rejudgingId)) {
@@ -163,7 +165,16 @@ public function getSubmissionList(
 
         if (isset($restrictions->externalDifference)) {
             if ($restrictions->externalDifference) {
-                $queryBuilder->andWhere('j.result != ej.result');
+                if ($restrictions->result === 'judging' || $restrictions->externalResult === 'judging') {
+                    // When either the local or external result is set to judging explicitly,
+                    // coalesce the result with a known non-null value, because in MySQL
+                    // 'correct' <> null is not true. By coalescing with '-' we prevent this.
+                    $queryBuilder
+                        ->andWhere('COALESCE(j.result, :dash) != COALESCE(ej.result, :dash)')
+                        ->setParameter('dash', '-');
+                } else {
+                    $queryBuilder->andWhere('j.result != ej.result');
+                }
             } else {
                 $queryBuilder->andWhere('j.result = ej.result');
             }
diff --git a/webapp/templates/jury/partials/submission_graph.html.twig b/webapp/templates/jury/partials/submission_graph.html.twig
index d33220e2a9..8be33868d1 100644
--- a/webapp/templates/jury/partials/submission_graph.html.twig
+++ b/webapp/templates/jury/partials/submission_graph.html.twig
@@ -18,7 +18,7 @@
             </div>
         </div>
     {% endif %}
-    {% if externalJudgement is not null and externalJudgement.result is not null %}
+    {% if externalJudgement is not null and externalJudgement.result is not null and externalJudging is defined %}
         <div class="card" style="display: inline-block" id="externalruntime">
             <div class="card-header">
                 <span id="graphs" style="font-weight: bold;">External Testcase CPU times
diff --git a/webapp/templates/jury/submission.html.twig b/webapp/templates/jury/submission.html.twig
index 6232830d8f..4b04e74b3a 100644
--- a/webapp/templates/jury/submission.html.twig
+++ b/webapp/templates/jury/submission.html.twig
@@ -551,11 +551,11 @@
                                 {{ externalRuns | displayTestcaseResults(externalJudgement.endtime is not empty, true) }}
                             </td>
                             <td>
-                                {% if externalSubmissionUrl and externalSubmissionUrl is not empty %}
+                                {% if externalSubmissionUrl is defined and externalSubmissionUrl is not empty %}
                                 <a href="{{ externalSubmissionUrl }}">
                                     {% endif %}
                                     external {{ externalJudgement.extjudgementid }}
-                                    {% if externalSubmissionUrl and externalSubmissionUrl is not empty %}
+                                    {% if externalSubmissionUrl is defined and externalSubmissionUrl is not empty %}
                                 </a>
                                 {% endif %}
                             </td>