diff --git a/src/DataFixtures/TaxonomyFixtures.php b/src/DataFixtures/TaxonomyFixtures.php
index 232db6058..3b00b08fc 100644
--- a/src/DataFixtures/TaxonomyFixtures.php
+++ b/src/DataFixtures/TaxonomyFixtures.php
@@ -51,13 +51,13 @@ private function loadTaxonomies(ObjectManager $manager): void
             foreach ($options as $key => $value) {
                 $taxonomy = $this->taxonomyRepository->factory(
                     $taxonomyDefinition['slug'],
-                    $key,
+                    (string) $key,
                     $value,
                     $taxonomyDefinition['has_sortorder'] ? $order++ : 0
                 );
 
                 $manager->persist($taxonomy);
-                $reference = 'taxonomy_' . $taxonomyDefinition['slug'] . '_' . Str::slug($key);
+                $reference = 'taxonomy_' . $taxonomyDefinition['slug'] . '_' . Str::slug((string) $key);
                 $this->addReference($reference, $taxonomy);
             }
         }