diff --git a/core/Migrations/Version28000Date20230803221055.php b/core/Migrations/Version28000Date20230803221055.php
index 8878a6f6cce9b..799eb15e06e91 100644
--- a/core/Migrations/Version28000Date20230803221055.php
+++ b/core/Migrations/Version28000Date20230803221055.php
@@ -52,9 +52,10 @@ public function changeSchema(IOutput $output, Closure $schemaClosure, array $opt
 			$column = $table->getColumn('user_id');
 			$column->setNotnull(false);
 
-			$table->addIndex(['user_id', 'app_id', 'identifier'], 'tp_tasks_uid_appid_ident');
-
-			$changed = true;
+			if (!$table->hasIndex('tp_tasks_uid_appid_ident')) {
+				$table->addIndex(['user_id', 'app_id', 'identifier'], 'tp_tasks_uid_appid_ident');
+				$changed = true;
+			}
 		}
 
 		if ($changed) {