diff --git a/EventListener/ContactSubscriber.php b/EventListener/ContactSubscriber.php
index 24cf17c35..267210d51 100644
--- a/EventListener/ContactSubscriber.php
+++ b/EventListener/ContactSubscriber.php
@@ -10,7 +10,6 @@
 use Mautic\LeadBundle\Event\LeadMergeEvent;
 use Mautic\LeadBundle\Event\LeadTimelineEvent;
 use Mautic\LeadBundle\LeadEvents;
-use MauticPlugin\CustomObjectsBundle\Entity\CustomItemXrefContact;
 use MauticPlugin\CustomObjectsBundle\Exception\NotFoundException;
 use MauticPlugin\CustomObjectsBundle\Model\CustomItemModel;
 use MauticPlugin\CustomObjectsBundle\Provider\ConfigProvider;
@@ -38,7 +37,7 @@ public static function getSubscribedEvents(): array
     {
         return [
             LeadEvents::TIMELINE_ON_GENERATE => 'onTimelineGenerate',
-            LeadEvents::LEAD_PRE_MERGE       => 'onCongactPreMerge',
+            LeadEvents::LEAD_POST_MERGE      => 'onContactMerge',
         ];
     }
 
@@ -74,41 +73,13 @@ public function onTimelineGenerate(LeadTimelineEvent $event): void
         }
     }
 
-    /**
-     * Moves the custom item links from the loser to the victor if they don't exist in the victor's list.
-     * Removes the remaining links from the loser.
-     */
-    public function onCongactPreMerge(LeadMergeEvent $event): void
+    public function onContactMerge(LeadMergeEvent $event): void
     {
         if (!$this->configProvider->pluginIsEnabled()) {
             return;
         }
 
-        $loser = $event->getLoser();
-
-        /** @var CustomItemXrefContact[] $loserLinks */
-        $loserLinks = $this->customItemXrefContactRepository->findBy(['contact' => $loser]);
-
-        if (!$loserLinks) {
-            return;
-        }
-
-        $victor = $event->getVictor();
-
-        /** @var CustomItemXrefContact[] $victorLinks */
-        $victorLinks    = $this->customItemXrefContactRepository->findBy(['contact' => $victor]);
-        $victorItemsIds = array_map(fn (CustomItemXrefContact $link) => $link->getCustomItem()->getId(), $victorLinks);
-
-        foreach ($loserLinks as $loserLink) {
-            if (!in_array($loserLink->getCustomItem()->getId(), $victorItemsIds)) {
-                $newLink = new CustomItemXrefContact($loserLink->getCustomItem(), $victor, $loserLink->getDateAdded());
-                $this->entityManager->persist($newLink);
-            }
-
-            $this->entityManager->remove($loserLink);
-        }
-
-        $this->entityManager->flush();
+        $this->customItemXrefContactRepository->mergeLead($event->getVictor(), $event->getLoser());
     }
 
     /**
diff --git a/Repository/CustomItemXrefContactRepository.php b/Repository/CustomItemXrefContactRepository.php
index 34d491e63..811f6281e 100644
--- a/Repository/CustomItemXrefContactRepository.php
+++ b/Repository/CustomItemXrefContactRepository.php
@@ -62,4 +62,32 @@ public function getContactIdsLinkedToCustomItem(int $customItemId, int $limit, i
             ->getQuery()
             ->getResult();
     }
+
+    public function mergeLead(Lead $victor, Lead $loser): void
+    {
+        // Move all custom item references to the victor lead, but only if the victor doesn't already have
+        // a reference to the custom item
+        $existingAlias = CustomItemXrefContact::TABLE_ALIAS.'_Check';
+
+        $this->createQueryBuilder(CustomItemXrefContact::TABLE_ALIAS)
+            ->update()
+            ->set(CustomItemXrefContact::TABLE_ALIAS.'.contact', ':victor')
+            ->where(CustomItemXrefContact::TABLE_ALIAS.'.contact = :loser')
+            ->andWhere(
+                $this->createQueryBuilder(CustomItemXrefContact::TABLE_ALIAS)
+                    ->expr()
+                    ->notIn(
+                        CustomItemXrefContact::TABLE_ALIAS.'.customItem',
+                        $this->createQueryBuilder($existingAlias)
+                            ->select('IDENTITY('.$existingAlias.'.customItem)')
+                            ->where($existingAlias.'.contact = :victor')
+                            ->getDQL()
+                    )
+            )
+            ->setParameter('victor', $victor->getId())
+            ->setParameter('loser', $loser->getId())
+            ->getQuery()
+            ->execute();
+
+    }
 }