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**
for line in self:
            taxes = line.taxes_id.compute_all(line.price_unit, line.order_id.currency_id, line.product_qty, product=line.product_id, partner=line.order_id.partner_id)
            line.update({
                'price_tax': taxes['total_included'] - taxes['total_excluded'],
                'price_total': taxes['total_included'],
                'price_subtotal': taxes['total_excluded'],
            })
    @api.multi
    def _compute_tax_id(self):
        for line in self:
            fpos = line.order_id.fiscal_position_id or line.order_id.partner_id.property_account_position_id
            
            taxes = line.product_id.supplier_taxes_id.filtered(lambda r: not line.company_id or r.company_id == line.company_id)
            line.taxes_id = fpos.map_tax(taxes, line.product_id, line.order_id.partner_id) if fpos else taxes
    @api.depends('invoice_lines.invoice_id.state')
    def _compute_qty_invoiced(self):
        for line in self:
            qty = 0.0
            for inv_line in line.invoice_lines:
                if inv_line.invoice_id.state not in ['cancel']:
                    if inv_line.invoice_id.type == 'in_invoice':
                        qty += inv_line.uom_id._compute_quantity(inv_line.quantity, line.product_uom)
                    elif inv_line.invoice_id.type == 'in_refund':
                        qty -= inv_line.uom_id._compute_quantity(inv_line.quantity, line.product_uom)
            line.qty_invoiced = qty
    @api.depends('order_id.state', 'move_ids.state')
    def _compute_qty_received(self):