Then I create some fields of selection type this WARNING appear for every field . 

I have this table as header... 

class FreightSettlement(models.Model):
    _name = 'freight.settlement'
    _description = 'Freight Settlement'

    name = fields.Char(string="Name")
    invoice_ids = fields.One2many("freight.settlement.invoice", "parent_id", string="Freight Settlement Invoice")
    state = fields.Selection(
        [
            ('draft', 'Draft'),
            ('done', 'Done'),
        ], default='draft', string='State'
    )

And this as detail... 

class FreightSettlementInvoice(models.Model):
    _name = "freight.settlement.invoice"
    _description = "Freight Settlement Invoice"

    parent_id = fields.Many2one("freight.settlement", string="Freight Settlement")
    parent_state = fields.Selection(
        [
            ('draft', 'Draft'),
            ('done', 'Done'),
        ], related='parent_id.state', string='State'
    )

Then in the server log I get this WARNING. 

2022-07-25 20:16:59,929 1 WARNING staging-data-2 odoo.fields: freight.settlement.invoice.parent_state: selection attribute will be ignored as the field is related

How to solve this WARNING?

Thanks in advance