I have some strange behavior when I inherit the sales order form view into my model/view.

I inherited the view into my model without changing the original view.

---

<record id="work_order_form" model="ir.ui.view">
        <field name="name">Extend the Sale Order</field>
        <field name="model">sale.order</field>
        <field name="inherit_id" ref="sale.view_order_form"/>
        <field name="mode">primary</field>
        <field name="arch" type="xml">

            <field name="payment_term_id" position="after">
                <field name='my_field'/>
            </field>

        </field>
    </record>

---

Therefore I used the primary field (see my code) and I get what I want. Well...

My new view shows the extended field (my_field) and the sales order form view does not, as it should.

Within the sales module so, if I open a quotation, I can see that the quotation form also have the additional field (my_field). But if I am correct both (sales order & quotations use the same view i.e. sale.order.form)

For some reason quotations now also use the extended view.

Some of the code for completeness:

---

To open the view I added:

 <!-- Action to open the Workorder list -->
    <act_window id="action_yacht_service" name="Workorders"
                res_model="sale.order" view_mode="tree,form"/>

    <!-- Menu item to open the Workorder list -->
    <menuitem id="menu_yacht_service" name="Workorder"
              parent="menu_yachtservice" action="action_yacht_service" sequence="2"/>

---

code to inherit the model:

from odoo import fields, models


class YachtService(models.Model):
    _name = 'yacht.service'
    _description = 'Workorder Data'

    name = fields.Char(string="Name")
    description = fields.Text(string="Description")
    cost = fields.Float(string="Cost")



class WorkorderInheritSale(models.Model):
    _inherit = 'sale.order'

   my_field = fields.Boolean(string="Is Workorder")
   my_field_2 = fields.Boolean(string="Is Platzhalter 2")

Really confusing, pls help.