I created an onchange function that link some object lines to the current one

     mo_lines_g1 = fields.One2many(comodel_name='object.order', inverse_name='mo_id1', copy=False )
    @api.onchange('date')    def change_date(self):          if self.date:
            g1=self.env['object.order'].search(['&'('date_order','>=',self.date),('date_order','<=',self.date)])            self.mo_lines_g1 = [(6,0, g1.ids )]

here everything is ok, but when I save the view, Odoo try to delete the linked lines from the object.order

so I tried to see what the write function send I found it send the old records :
vals[ 'mo_lines_g1'] = [[2, 61, False], [2, 62, False], [2, 63, False]]

normaly it must be :
vals['mo_lines_g1']=[] # or [(6,0,[])]

any ideas ?