diff --git a/src/pif_compiler/functions/common_func.py b/src/pif_compiler/functions/common_func.py
index 333dac4..e24703c 100644
--- a/src/pif_compiler/functions/common_func.py
+++ b/src/pif_compiler/functions/common_func.py
@@ -130,28 +130,27 @@ async def generate_project_source_pdfs(project, output_dir: str = "pdfs") -> lis
                 log.warning(f"PDF tox non generato per {pdf_name}")
 
         # --- COSING PDF ---
+        # Un solo PDF per ingrediente (il primo CosingInfo con reference valida).
         if ing.cosing_info:
-            seen_refs = set()
-            for cosing in ing.cosing_info:
-                if not cosing.reference or cosing.reference in seen_refs:
-                    continue
-                seen_refs.add(cosing.reference)
+            pdf_name = f"{pi.cas}_cosing"
+            pdf_path = os.path.join(output_dir, f"{pdf_name}.pdf")
 
-                pdf_name = f"{pi.cas}_cosing"
-                pdf_path = os.path.join(output_dir, f"{pdf_name}.pdf")
-
-                if os.path.exists(pdf_path):
-                    generated.append(pdf_path)
-                    continue
-
-                log.info(f"Download COSING PDF: {pdf_name} (reference={cosing.reference})")
-                content = cosing_download(cosing.reference)
-                if isinstance(content, bytes):
-                    with open(pdf_path, 'wb') as f:
-                        f.write(content)
-                    generated.append(pdf_path)
-                else:
-                    log.warning(f"COSING PDF non scaricato per {pdf_name}: {content}")
+            if os.path.exists(pdf_path):
+                generated.append(pdf_path)
+            else:
+                reference = next(
+                    (c.reference for c in ing.cosing_info if c.reference),
+                    None
+                )
+                if reference:
+                    log.info(f"Download COSING PDF: {pdf_name} (reference={reference})")
+                    content = cosing_download(reference)
+                    if isinstance(content, bytes):
+                        with open(pdf_path, 'wb') as f:
+                            f.write(content)
+                        generated.append(pdf_path)
+                    else:
+                        log.warning(f"COSING PDF non scaricato per {pdf_name}: {content}")
 
     log.info(f"Generazione fonti completata: {len(generated)} PDF generati")
     return generated
@@ -190,10 +189,14 @@ def create_sources_zip(pdf_paths: list, zip_path: str) -> str:
     if zip_dir:
         os.makedirs(zip_dir, exist_ok=True)
 
+    seen_names: set[str] = set()
     with zipfile.ZipFile(zip_path, 'w', zipfile.ZIP_DEFLATED) as zf:
         for path in pdf_paths:
-            if os.path.exists(path):
-                zf.write(path, os.path.basename(path))
+            name = os.path.basename(path)
+            if not os.path.exists(path) or name in seen_names:
+                continue
+            seen_names.add(name)
+            zf.write(path, name)
 
     log.info(f"ZIP creato: {zip_path} ({len(pdf_paths)} file)")
     return zip_path