If Invoice is generated from the Sale order, we get an error:

Server Traceback (most recent call last):
  File "/opt/openerp/web/addons/web/session.py", line 90, in send
    return openerp.netsvc.dispatch_rpc(service_name, method, args)
  File "/opt/openerp/server/openerp/netsvc.py", line 293, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/opt/openerp/server/openerp/service/web_services.py", line 626, in dispatch
    res = fn(db, uid, *params)
  File "/opt/openerp/server/openerp/osv/osv.py", line 188, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File "/opt/openerp/server/openerp/osv/osv.py", line 131, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/opt/openerp/server/openerp/osv/osv.py", line 197, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/opt/openerp/addons/audittrail/audittrail.py", line 514, in execute_cr
    return fct_src(cr, uid, model, method, *args, **kw)
  File "/opt/openerp/server/openerp/osv/osv.py", line 185, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/opt/openerp/addons/sale/wizard/sale_make_invoice_advance.py", line 170, in create_invoices
    res = sale_obj.manual_invoice(cr, uid, sale_ids, context)
  File "/opt/openerp/addons/sale/sale.py", line 435, in manual_invoice
    wf_service.trg_validate(uid, 'sale.order', id, 'manual_invoice', cr)
  File "/opt/openerp/server/openerp/workflow/wkf_service.py", line 119, in trg_validate
    res2 = instance.validate(cr, id, ident, signal)
  File "/opt/openerp/server/openerp/workflow/instance.py", line 43, in validate
    workitem.process(cr, witem, ident, signal, force_running, stack=stack)
  File "/opt/openerp/server/openerp/workflow/workitem.py", line 60, in process
    ok = _split_test(cr, workitem, activity['split_mode'], ident, signal, stack)
  File "/opt/openerp/server/openerp/workflow/workitem.py", line 175, in _split_test
    _join_test(cr, t[0], t[1], ident, stack)
  File "/opt/openerp/server/openerp/workflow/workitem.py", line 183, in _join_test
    create(cr,[activity], inst_id, ident, stack)
  File "/opt/openerp/server/openerp/workflow/workitem.py", line 40, in create
    process(cr, res, ident, stack=stack)
  File "/opt/openerp/server/openerp/workflow/workitem.py", line 52, in process
    result = _execute(cr, workitem, activity, ident, stack)
  File "/opt/openerp/server/openerp/workflow/workitem.py", line 127, in _execute
    id_new = wkf_expr.execute(cr, ident, workitem, activity)
  File "/opt/openerp/server/openerp/workflow/wkf_expr.py", line 67, in execute
    return _eval_expr(cr, ident, workitem, activity['action'])
  File "/opt/openerp/server/openerp/workflow/wkf_expr.py", line 57, in _eval_expr
    ret = eval(line, env, nocopy=True)
  File "/opt/openerp/server/openerp/tools/safe_eval.py", line 241, in safe_eval
    return eval(test_expr(expr, _SAFE_OPCODES, mode=mode), globals_dict, locals_dict)
  File "", line 1, in <module>
  File "/opt/openerp/server/openerp/osv/orm.py", line 374, in function_proxy
    return attr(self._cr, self._uid, [self._id], *args, **kwargs)
  File "/opt/openerp/addons/sale_stock/sale_stock.py", line 192, in action_invoice_create
    res = super(sale_order,self).action_invoice_create( cr, uid, ids, grouped=grouped, states=states, date_invoice = date_invoice, context=context)
  File "/opt/openerp/addons/sale/sale.py", line 533, in action_invoice_create
    res = self._make_invoice(cr, uid, order, il, context=context)
  File "/opt/openerp/addons/sale/sale.py", line 405, in _make_invoice
    data = inv_obj.onchange_payment_term_date_invoice(cr, uid, [inv_id], inv['payment_term'], time.strftime(DEFAULT_SERVER_DATE_FORMAT))
  File "/opt/openerp/addons/account/account_invoice.py", line 531, in onchange_payment_term_date_invoice
    if not payment_term_id and inv_record.date_due:
AttributeError: 'browse_record_list' object has no attribute 'date_due'