diff --git a/src/CoreShop/Bundle/ResourceBundle/Doctrine/ORM/EntityMerger.php b/src/CoreShop/Bundle/ResourceBundle/Doctrine/ORM/EntityMerger.php
index dd4c28fd63..8a254bc88a 100644
--- a/src/CoreShop/Bundle/ResourceBundle/Doctrine/ORM/EntityMerger.php
+++ b/src/CoreShop/Bundle/ResourceBundle/Doctrine/ORM/EntityMerger.php
@@ -127,6 +127,14 @@ private function checkAssociations($entity, $managedCopy, array &$visited): void
                 //Reset new Data, for some reason the line above resets newData
                 $newData = $class->reflFields[$assoc['fieldName']]->getValue($entity);
 
+                if (!$newCollection instanceof PersistentCollection) {
+                    $newCollection = new PersistentCollection(
+                        $this->em,
+                        $class,
+                        $newCollection
+                    );
+                }
+
                 $this->mergeCollection($origData, $newData, $assoc, static function ($foundEntry) use ($newCollection) {
                     $newCollection->removeElement($foundEntry);
                 }, $visited);
diff --git a/src/CoreShop/Bundle/ResourceBundle/Resources/public/pimcore/js/coreExtension/data/coreShopRelations.js b/src/CoreShop/Bundle/ResourceBundle/Resources/public/pimcore/js/coreExtension/data/coreShopRelations.js
index b470ed6ead..6f80ee434e 100644
--- a/src/CoreShop/Bundle/ResourceBundle/Resources/public/pimcore/js/coreExtension/data/coreShopRelations.js
+++ b/src/CoreShop/Bundle/ResourceBundle/Resources/public/pimcore/js/coreExtension/data/coreShopRelations.js
@@ -86,7 +86,7 @@ pimcore.object.classes.data.coreShopRelations = Class.create(coreshop.object.cla
                     {
                         xtype: 'combo',
                         fieldLabel: t("coreshop_allowed_stack"),
-                        name: "classes",
+                        name: "stacks",
                         id: 'coreshop_relation_stack_' + this.uniqeFieldId,
                         value: this.datax.stack,
                         store: stacks,