Al anular una boleta electrónica generada desde el punto de venta aparece el siguiente error ¿Alguna idea?

Odoo Server Error

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/qweb.py", line 343, in _compiled_fn
    return compiled(self, append, new, options, log)
  File "<template>", line 1, in template_l10n_cl_dte_point_of_sale_report_boleta_sii_barcode_layout_812
AttributeError: 'NoneType' object has no attribute 'sii'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/main.py", line 1620, in report_download
    response = self.report_routes(reportname, docids=docids, converter='pdf')
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 515, in response_wrap
    response = f(*args, **kw)
  File "/opt/odoo/addons/report_xlsx/controllers/main.py", line 43, in report_routes
    reportname, docids, converter, **data
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 515, in response_wrap
    response = f(*args, **kw)
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/main.py", line 1569, in report_routes
    pdf = report.with_context(context).render_qweb_pdf(docids, data=data)[0]
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_actions_report.py", line 628, in render_qweb_pdf
    html = self.with_context(context).render_qweb_html(res_ids, data=data)[0]
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_actions_report.py", line 666, in render_qweb_html
    return self.render_template(self.report_name, data), 'html'
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_actions_report.py", line 470, in render_template
    return view_obj.render_template(template, values)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_ui_view.py", line 1201, in render_template
    return self.browse(self.get_view_id(template)).render(values, engine)
  File "/usr/lib/python3/dist-packages/odoo/addons/web_editor/models/ir_ui_view.py", line 27, in render
    return super(IrUiView, self).render(values=values, engine=engine)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_ui_view.py", line 1210, in render
    return self.env[engine].render(self.id, qcontext)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/ir_qweb.py", line 57, in render
    return super(IrQWeb, self).render(id_or_xml_id, values=values, **context)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/qweb.py", line 272, in render
    self.compile(template, options)(self, body.append, values or {})
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/qweb.py", line 345, in _compiled_fn
    raise e
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/qweb.py", line 343, in _compiled_fn
    return compiled(self, append, new, options, log)
  File "<template>", line 1, in template_992_747
  File "<template>", line 2, in body_call_content_746
  File "<template>", line 3, in foreach_745
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/qweb.py", line 345, in _compiled_fn
    raise e
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/qweb.py", line 343, in _compiled_fn
    return compiled(self, append, new, options, log)
  File "<template>", line 1, in template_l10n_cl_dte_point_of_sale_report_pos_boleta_ticket_body_767
  File "<template>", line 2, in body_call_content_766
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/qweb.py", line 350, in _compiled_fn
    raise QWebException("Error to render compiling AST", e, path, node and etree.tostring(node[0], encoding='unicode'), name)
odoo.addons.base.ir.ir_qweb.qweb.QWebException: 'NoneType' object has no attribute 'sii'
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/addons/base/ir/ir_qweb/qweb.py", line 343, in _compiled_fn
    return compiled(self, append, new, options, log)
  File "<template>", line 1, in template_l10n_cl_dte_point_of_sale_report_boleta_sii_barcode_layout_812
AttributeError: 'NoneType' object has no attribute 'sii'

Error to render compiling AST
AttributeError: 'NoneType' object has no attribute 'sii'
Template: l10n_cl_dte_point_of_sale.report_boleta_sii_barcode_layout
Path: /templates/t/div/div[2]/p/t[3]
Node: <t t-if="o.document_class_id.sii_code in [ 61 ]" t-esc="www.sii.cl"/>