### Steps to reproduce:

- In the settings enable: Click & Collect, Multi Steps Routes
- Set up a a demo payment provider
- Create a second warehouse for the company of your website
- Create a storable product, put units in stock for WH2 and publish it on the website
- As an anonymous portal user, add one unit to your chart using the "pickup in store" button > select warehouse 2
- Click on checkout fill the form and pay
#### > The sale order was attached to the warehouse 1 and the associated delivery is therefore erroneous.

### Cause of the issue:

Once a product is added to the chart, the sale order is created and since you added it using the pick up in store option, the sale order's warehouse_id and pickup location will be correcty updated by these calls: https://github.com/odoo/odoo/blob/785ea79c9ccd655079abeb4b13806e8174968dc3/addons/website_sale_collect/controllers/delivery.py#L22-L36 https://github.com/odoo/odoo/blob/785ea79c9ccd655079abeb4b13806e8174968dc3/addons/website_sale_collect/models/sale_order.py#L34-L36 However, during the checkout you will set a `partner_id` on the SO this will mark the `warhouse_id` field as a field to recompute because of the chain of dependencies of its compute methods: https://github.com/odoo/odoo/blob/785ea79c9ccd655079abeb4b13806e8174968dc3/addons/sale/models/sale_order.py#L463-L464 https://github.com/odoo/odoo/blob/785ea79c9ccd655079abeb4b13806e8174968dc3/addons/sale_stock/models/sale_order.py#L185-L186 And, the computed value of the `warehouse_id` will then override the current one..

opw-4737862
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Forward-Port-Of: odoo/odoo#208271
Forward-Port-Of: odoo/odoo#208056