diff --git a/l10n_br_fiscal/models/res_partner.py b/l10n_br_fiscal/models/res_partner.py
index b173a2944573..b252c826a584 100644
--- a/l10n_br_fiscal/models/res_partner.py
+++ b/l10n_br_fiscal/models/res_partner.py
@@ -2,7 +2,7 @@
 # Copyright (C) 2020 - TODAY Luis Felipe Mileo - KMEE
 # License AGPL-3 - See http://www.gnu.org/licenses/agpl-3.0.html
 
-from odoo import api, fields, models
+from odoo import _, api, fields, models
 
 from ..constants.fiscal import (
     FINAL_CUSTOMER,
@@ -136,3 +136,9 @@ def _commercial_fields(self):
             "inscr_est",
             "inscr_mun",
         ]
+
+    @api.constrains("is_anonymous_consumer")
+    def _check_anonymous_consumer(self):
+        for p in self:
+            if p.is_anonymous_consumer and p.cnpj_cpf:
+                raise ValueError(_("Anonymous consumer cannot have a CNPJ/CPF number."))
diff --git a/l10n_br_pos_nfce/models/pos_config.py b/l10n_br_pos_nfce/models/pos_config.py
index dfbdeef3288a..30099e341d4a 100644
--- a/l10n_br_pos_nfce/models/pos_config.py
+++ b/l10n_br_pos_nfce/models/pos_config.py
@@ -27,19 +27,13 @@ class PosConfig(models.Model):
 
     nfce_document_serie_sequence_number_next = fields.Integer(
         string="Document Serie Number",
-        default=lambda self: self._default_next_number(),
+        related="nfce_document_serie_id.internal_sequence_id.number_next_actual",
     )
 
     nfce_city_ibge_code = fields.Char(
         related="company_id.city_id.ibge_code",
     )
 
-    def _default_next_number(self):
-        if not self.nfce_document_serie_id:
-            return 1
-
-        return self.nfce_document_serie_id.internal_sequence_id.number_next_actual
-
     def update_nfce_serie_number(self, serie_number):
         if self.nfce_document_serie_sequence_number_next < serie_number:
             self.nfce_document_serie_sequence_number_next = serie_number