diff --git a/IOB-WIN-NEXT/IobSoap/Gomba.cs b/IOB-WIN-NEXT/IobSoap/Gomba.cs
index 571ea9da..ebefe7aa 100644
--- a/IOB-WIN-NEXT/IobSoap/Gomba.cs
+++ b/IOB-WIN-NEXT/IobSoap/Gomba.cs
@@ -246,7 +246,9 @@ namespace IOB_WIN_NEXT.IobSoap
                         outVal.Add("lastRecOut", formatPesata(firstRec, false));
                     }
                     // la aggiungo alle pesate archiviate...
-                    listPesateArch.Add(firstRec);
+                    var tmpPesate = listPesateArch;
+                    tmpPesate.Add(firstRec);
+                    listPesateArch = tmpPesate;
                 }
 #if false