diff --git a/app/core/ingestion/ingestion_processor.py b/app/core/ingestion/ingestion_processor.py
index 7a98a30..4f164e7 100644
--- a/app/core/ingestion/ingestion_processor.py
+++ b/app/core/ingestion/ingestion_processor.py
@@ -307,6 +307,31 @@ class IngestionService:
                             logger.info(f"   -> Hash-Unterschied: Erste unterschiedliche Position: {diff_pos}")
                         else:
                             logger.info(f"   -> Hash-Unterschied: Längen unterschiedlich (new={len(new_h)}, old={len(old_h)})")
+                        
+                        # WP-24c v4.5.9-DEBUG: Logge Hash-Input für Diagnose
+                        from app.core.ingestion.ingestion_note_payload import _get_hash_source_content
+                        hash_mode = self.active_hash_mode or 'full'
+                        hash_input = _get_hash_source_content(note_pl, hash_mode)
+                        logger.info(f"   -> Hash-Input (erste 200 Zeichen): {hash_input[:200]}...")
+                        logger.info(f"   -> Hash-Input Länge: {len(hash_input)}")
+                        
+                        # WP-24c v4.5.9-DEBUG: Vergleiche auch Body-Länge und Frontmatter
+                        new_body = str(note_pl.get("body", "")).strip()
+                        old_body = str(old_payload.get("body", "")).strip() if old_payload else ""
+                        logger.info(f"   -> Body-Länge: new={len(new_body)}, old={len(old_body)}")
+                        if len(new_body) != len(old_body):
+                            logger.warning(f"   -> ⚠️ Body-Länge unterschiedlich! Mögliche Ursache: Parsing-Unterschiede")
+                        
+                        new_fm = note_pl.get("frontmatter", {})
+                        old_fm = old_payload.get("frontmatter", {}) if old_payload else {}
+                        logger.info(f"   -> Frontmatter-Keys: new={sorted(new_fm.keys())}, old={sorted(old_fm.keys())}")
+                        # Prüfe relevante Frontmatter-Felder
+                        relevant_keys = ["title", "type", "status", "tags", "chunking_profile", "chunk_profile", "retriever_weight", "split_level", "strict_heading_split"]
+                        for key in relevant_keys:
+                            new_val = new_fm.get(key)
+                            old_val = old_fm.get(key)
+                            if new_val != old_val:
+                                logger.warning(f"   -> ⚠️ Frontmatter '{key}' unterschiedlich: new={new_val}, old={old_val}")
                 else:
                     # WP-24c v4.5.9: Wenn Hash fehlt, als geändert behandeln (Sicherheit)
                     logger.warning(f"⚠️ [CHANGE-DETECTION] Hash fehlt für '{note_id}': new_h={bool(new_h)}, old_h={bool(old_h)}")