diff --git a/src/components/pages/studio/hooks/useBatchSubmit.ts b/src/components/pages/studio/hooks/useBatchSubmit.ts
index 6a8a7017..518e48dc 100644
--- a/src/components/pages/studio/hooks/useBatchSubmit.ts
+++ b/src/components/pages/studio/hooks/useBatchSubmit.ts
@@ -9,7 +9,8 @@ import {
   hasActionLoras,
 } from "../constants/duration-options";
 
-const BATCH_SIZE = 5;
+// Serialized to avoid concurrent auth refresh races (see fix/session-refresh-race on backend)
+const BATCH_SIZE = 1;
 
 export const useBatchSubmit = () => {
   const images = useStudioStore((s) => s.images);
diff --git a/src/hooks/useHttpInterceptors.ts b/src/hooks/useHttpInterceptors.ts
index 19d27219..6e1646e6 100644
--- a/src/hooks/useHttpInterceptors.ts
+++ b/src/hooks/useHttpInterceptors.ts
@@ -28,6 +28,8 @@ type ResponseGeneratorProps = {
   logout: () => Promise<void>;
 };
 
+let isLoggingOut = false;
+
 const generateResponseInterceptor = async ({
   logout,
 }: ResponseGeneratorProps) => {
@@ -38,14 +40,17 @@ const generateResponseInterceptor = async ({
     (response) => response,
     async (error) => {
       if (error?.response?.status === 401) {
-        // Handle unauthorized error
-        queryClient.clear();
-        await logout();
-        router.navigate(ROUTES.SIGNIN);
+        if (!isLoggingOut) {
+          isLoggingOut = true;
+          queryClient.clear();
+          await logout();
+          router.navigate(ROUTES.SIGNIN);
+          isLoggingOut = false;
+        }
         return Promise.reject(error);
       }
 
-      return error.response;
+      return Promise.reject(error);
     },
   );
 };