diff --git a/src/main/java/com/lowagie/text/pdf/PdfStamperImp.java b/src/main/java/com/lowagie/text/pdf/PdfStamperImp.java
index <HASH>..<HASH> 100644
--- a/src/main/java/com/lowagie/text/pdf/PdfStamperImp.java
+++ b/src/main/java/com/lowagie/text/pdf/PdfStamperImp.java
@@ -938,6 +938,7 @@ class PdfStamperImp extends PdfWriter {
             PdfReader.killIndirect(iFields);
             acrodic.put(PdfName.FIELDS, new PdfArray());
         }
+        acrodic.remove(PdfName.SIGFLAGS);
 //        PdfReader.killIndirect(acro);
 //        reader.getCatalog().remove(PdfName.ACROFORM);
     }
Remove the sigflags when flattening.