Impacted versions:
* 11.0

Steps to reproduce:
* Create company A
* Create company B
* Admin user with both companies but currently in company B
* Create Demo user only with company B
* Create fiscal position A to company A
* Create fiscal position B to company B
* Create vendor with fiscal position A with company A and the same vendor with fiscal position B in company B
* Create product and add the vendor created before
* Set like **Create a draft purchase order**
* Logging with Demo user
* Create sale order with one sale order line with route **make to order**
* Validate sale order

Current behavior:
The purchase order created by sale order has the fiscal position **company A**

Expected behavior:
The purchase order must have fiscal position **company B**
self.ensure_one()
        if 'state' in init_values and self.state == 'purchase':
            return 'purchase.mt_rfq_approved'
        elif 'state' in init_values and self.state == 'to approve':
            return 'purchase.mt_rfq_confirmed'
        elif 'state' in init_values and self.state == 'done':
            return 'purchase.mt_rfq_done'
        return super(PurchaseOrder, self)._track_subtype(init_values)
    @api.onchange('partner_id', 'company_id')
    def onchange_partner_id(self):
        if not self.partner_id:
            self.fiscal_position_id = False
            self.payment_term_id = False
            self.currency_id = False
        else:
            self.fiscal_position_id = self.env['account.fiscal.position'].with_context(company_id=self.company_id.id).get_fiscal_position(self.partner_id.id)
            self.payment_term_id = self.partner_id.property_supplier_payment_term_id.id
            self.currency_id = self.partner_id.property_purchase_currency_id.id or self.env.user.company_id.currency_id.id
        return {}
    @api.onchange('fiscal_position_id')
    def _compute_tax_id(self):
        """
        Trigger the recompute of the taxes if the fiscal position is changed on the PO.
        """
        for order in self:
            order.order_line._compute_tax_id()
    @api.onchange('partner_id')
    def onchange_partner_id_warning(self):