diff --git a/modules/services/serviceAi/subStructureFilling.py b/modules/services/serviceAi/subStructureFilling.py
index d84ddfcc..3de39418 100644
--- a/modules/services/serviceAi/subStructureFilling.py
+++ b/modules/services/serviceAi/subStructureFilling.py
@@ -1571,7 +1571,7 @@ class StructureFiller:
                     chapterIndex=0,  # Not used for sequential logic anymore
                     totalChapters=totalChapters,
                     chapterId=taskInfo["chapterId"],
-                    chapterOperationId=f"{fillOperationId}_chapter_{taskInfo['chapterId']}",
+                    chapterOperationId=fillOperationId,  # Use fillOperationId as parent (no chapter-level ops in parallel mode)
                     fillOperationId=fillOperationId,
                     contentParts=contentParts,
                     userPrompt=userPrompt,