diff --git a/app/workers/study_session_analysis_worker.py b/app/workers/study_session_analysis_worker.py
index 7571150..361a920 100644
--- a/app/workers/study_session_analysis_worker.py
+++ b/app/workers/study_session_analysis_worker.py
@@ -287,6 +287,10 @@ async def run_session_analysis_job(session: AsyncSession, job: StudyQuizSessionJ
             now=ts,
         )
 
+        # 이전 attempt 의 error_code (예: llm_timeout) 가 잔존하면 운영 분석 혼선.
+        # completed 박을 때 명시 clear.
+        job.error_code = None
+        job.error_message = None
         job.status = "completed"
         job.completed_at = ts
         return