--- mutt-1.5.21/copy.c
+++ mutt-1.5.21/copy.c	2014-03-25 08:42:27.466839319 +0000
@@ -254,6 +254,7 @@ mutt_copy_hdr (FILE *in, FILE *out, LOFF
     {
       if (!address_header_decode (&this_one))
 	rfc2047_decode (&this_one);
+      this_one_len = mutt_strlen (this_one);
     }
     
     if (!headers[x])