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**
addons/purchase/models/purchase.py
from datetime import datetime
from dateutil.relativedelta import relativedelta
from odoo import api, fields, models, SUPERUSER_ID, _
from odoo.tools import DEFAULT_SERVER_DATETIME_FORMAT
from odoo.tools.float_utils import float_is_zero, float_compare
from odoo.exceptions import UserError, AccessError
from odoo.tools.misc import formatLang
from odoo.addons.base.res.res_partner import WARNING_MESSAGE, WARNING_HELP
import odoo.addons.decimal_precision as dp
class PurchaseOrder(models.Model):
    _name = "purchase.order"
    _inherit = ['mail.thread', 'ir.needaction_mixin']
    _description = "Purchase Order"
    _order = 'date_order desc, id desc'
    @api.depends('order_line.price_total')
    def _amount_all(self):