diff --git a/klausur-service/backend/ocr_pipeline_geometry.py b/klausur-service/backend/ocr_pipeline_geometry.py
index 1c48adc..510c6c8 100644
--- a/klausur-service/backend/ocr_pipeline_geometry.py
+++ b/klausur-service/backend/ocr_pipeline_geometry.py
@@ -801,11 +801,13 @@ async def set_exclude_regions(session_id: str, body: _ExcludeRegionsBatchIn):
     sr = session.get("structure_result") or {}
     sr["exclude_regions"] = [r.model_dump() for r in body.regions]
 
-    await update_session_db(session_id, structure_result=sr)
+    # Invalidate grid so it rebuilds with new exclude regions
+    await update_session_db(session_id, structure_result=sr, grid_editor_result=None)
 
     # Update cache
     if session_id in _cache:
         _cache[session_id]["structure_result"] = sr
+        _cache[session_id].pop("grid_editor_result", None)
 
     return {
         "session_id": session_id,
@@ -830,10 +832,12 @@ async def delete_exclude_region(session_id: str, region_index: int):
     removed = regions.pop(region_index)
     sr["exclude_regions"] = regions
 
-    await update_session_db(session_id, structure_result=sr)
+    # Invalidate grid so it rebuilds with new exclude regions
+    await update_session_db(session_id, structure_result=sr, grid_editor_result=None)
 
     if session_id in _cache:
         _cache[session_id]["structure_result"] = sr
+        _cache[session_id].pop("grid_editor_result", None)
 
     return {
         "session_id": session_id,