I just added a custom related field in sale order line.

Now the issue is that while adding section or note in order line this custom field is not allowing me to do so. Because when I erase this field everything is working fine for me.

class SaleOrderLineInherit(models.Model):
_inherit = ['sale.order.line']

tran_service_type = fields.Many2one(related='product_id.product_tmpl_id.tran_service_type', string='TS Pairs')