diff --git a/rag/app/manual.py b/rag/app/manual.py
index 1eb86a043..363c6e9e7 100644
--- a/rag/app/manual.py
+++ b/rag/app/manual.py
@@ -219,23 +219,27 @@ def chunk(filename, binary=None, from_page=0, to_page=100000,
         )
 
         def _normalize_section(section):
-            # pad section to length 3: (txt, sec_id, poss)
-            if len(section) == 1:
+            # Pad/normalize to (txt, layout, positions)
+            if not isinstance(section, (list, tuple)):
+                section = (section, "", [])
+            elif len(section) == 1:
                 section = (section[0], "", [])
             elif len(section) == 2:
                 section = (section[0], "", section[1])
-            elif len(section) != 3:
-                raise ValueError(f"Unexpected section length: {len(section)} (value={section!r})")
+            else:
+                section = (section[0], section[1], section[2])
 
             txt, layoutno, poss = section
             if isinstance(poss, str):
                 poss = pdf_parser.extract_positions(poss)
-                first = poss[0]          # tuple: ([pn], x1, x2, y1, y2)
-                pn = first[0]
-
-                if isinstance(pn, list):
-                    pn = pn[0]           # [pn] -> pn
+                if poss:
+                    first = poss[0]  # tuple: ([pn], x1, x2, y1, y2)
+                    pn = first[0]
+                    if isinstance(pn, list) and pn:
+                        pn = pn[0]  # [pn] -> pn
                     poss[0] = (pn, *first[1:])
+            if not poss:
+                poss = []
 
             return (txt, layoutno, poss)