don't emit this pseudo header to clients.

src/pEpMIME.cc

@@ -144,6 +144,9 @@ message* parse_message(const char* mime_text, size_t length, bool* raise_attachm
     {
         stringpair_list_t* forwarded = stringpair_list_find(msg->opt_fields, pEpMIME::Pseudo_Header_Forwarded.data());
         *raise_attachment = (forwarded && forwarded->value && forwarded->value->value==std::string{"no"});
+        
+        // don't emit this pseudo header to clients.
+        msg->opt_fields = stringpair_list_delete_by_key(msg->opt_fields, pEpMIME::Pseudo_Header_Forwarded.data());
     }
     
     return msg;