diff --git a/klausur-service/backend/ocr_pipeline_api.py b/klausur-service/backend/ocr_pipeline_api.py
index 0542209..e0bcf5c 100644
--- a/klausur-service/backend/ocr_pipeline_api.py
+++ b/klausur-service/backend/ocr_pipeline_api.py
@@ -708,15 +708,19 @@ async def detect_columns(session_id: str):
         "duration_seconds": round(duration, 2),
     }
 
-    # Persist to DB
+    # Persist to DB — also invalidate downstream results (rows, words)
     await update_session_db(
         session_id,
         column_result=column_result,
+        row_result=None,
+        word_result=None,
         current_step=3,
     )
 
     # Update cache
     cached["column_result"] = column_result
+    cached.pop("row_result", None)
+    cached.pop("word_result", None)
 
     col_count = len([c for c in columns if c["type"].startswith("column")])
     logger.info(f"OCR Pipeline: columns session {session_id}: "
@@ -737,10 +741,13 @@ async def set_manual_columns(session_id: str, req: ManualColumnsRequest):
         "method": "manual",
     }
 
-    await update_session_db(session_id, column_result=column_result)
+    await update_session_db(session_id, column_result=column_result,
+                           row_result=None, word_result=None)
 
     if session_id in _cache:
         _cache[session_id]["column_result"] = column_result
+        _cache[session_id].pop("row_result", None)
+        _cache[session_id].pop("word_result", None)
 
     logger.info(f"OCR Pipeline: manual columns session {session_id}: "
                 f"{len(req.columns)} columns set")
@@ -919,14 +926,16 @@ async def detect_rows(session_id: str):
         "duration_seconds": round(duration, 2),
     }
 
-    # Persist to DB
+    # Persist to DB — also invalidate word_result since rows changed
     await update_session_db(
         session_id,
         row_result=row_result,
+        word_result=None,
         current_step=4,
     )
 
     cached["row_result"] = row_result
+    cached.pop("word_result", None)
 
     logger.info(f"OCR Pipeline: rows session {session_id}: "
                 f"{len(rows)} rows detected ({duration:.2f}s): {type_counts}")
@@ -947,10 +956,11 @@ async def set_manual_rows(session_id: str, req: ManualRowsRequest):
         "method": "manual",
     }
 
-    await update_session_db(session_id, row_result=row_result)
+    await update_session_db(session_id, row_result=row_result, word_result=None)
 
     if session_id in _cache:
         _cache[session_id]["row_result"] = row_result
+        _cache[session_id].pop("word_result", None)
 
     logger.info(f"OCR Pipeline: manual rows session {session_id}: "
                 f"{len(req.rows)} rows set")