diff --git a/src/sharedHelpers/rollbackPhotos.ts b/src/sharedHelpers/rollbackPhotos.ts
index 9b7ab74c7..45a6c477b 100644
--- a/src/sharedHelpers/rollbackPhotos.ts
+++ b/src/sharedHelpers/rollbackPhotos.ts
@@ -56,7 +56,7 @@ export const backupObservationPhotos = async (
     );
 
     const mappings = results.filter(
-      ( m ): m is BackupMapping => m !== null,
+      m => m !== null,
     );
     logger.info(
       `backupObservationPhotos: backed up ${mappings.length} photos`,