Apr 4 [UPDT] : Bug Fixed

multi_branch_base/views/branch_account_move_views.xml

@@ -7,8 +7,7 @@
         	<field name="inherit_id" ref="account.view_move_form"/>
 			<field name="arch" type="xml">
                 <xpath expr="//field[@name='invoice_date']" position="after">
-                    <field name="branch_id" options="{'no_create': True}" required="1"
-						   attrs="{'readonly': [('state', '!=', 'draft')]}"/>
+                    <field name="branch_id" options="{'no_create': True}" required="1"/>
                 </xpath>
                 <xpath expr="//field[@name='invoice_line_ids']/tree/field[@name='account_id']" position="attributes">
                           <attribute name="domain">[('deprecated', '=', False), ('account_type', 'not in', ('asset_receivable', 'liability_payable')), ('company_id', '=', parent.company_id), ('is_off_balance', '=', False), '|', ('branch_id', '=', parent.branch_id),('branch_id', '=', False)]</attribute>

multi_branch_pos/models/pos_orders.py

@@ -23,7 +23,6 @@
 import logging
 from odoo import fields, models
 
-
 _logger = logging.getLogger(__name__)
 
 
@@ -36,3 +35,10 @@ class BranchPosOrder(models.Model):
                                 related='session_id.branch_id',
                                 string='Branch', help='Branches allowed',
                                 store=True)
+
+    def _generate_pos_order_invoice(self):
+        res = super(BranchPosOrder, self)._generate_pos_order_invoice()
+        if self.account_move:
+            self.account_move.write({'branch_id': self.branch_id})
+
+        return res