diff --git a/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
index 414206f..50d8e68 100644
--- a/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
+++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
@@ -581,6 +581,9 @@ public function buildConfirmForm(array $form, FormStateInterface $form_state) {
       ksort($table_data[$source_module]);
     }
 
+    // Fetch the system data at the first opportunity.
+    $system_data = $form_state->get('system_data');
+
     $unmigrated_source_modules = array_diff_key($system_data['module'], $table_data);
 
     // Missing migrations.