A four digit year could not be found Data missing when using protected dates in laravel

i am trying to updating ( date_of_completion ) field, but it showing error , if i removed protected $dates from model it works

error

A four digit year could not be found
Data missing

MODEL

<?php

namespace App;
use Illuminate\Notifications\Notifiable;
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Database\Eloquent\Model;

class Student extends Model
{

    protected $dates = ['date_of_join','date_of_completion','dob'];
    protected $table = 'student_lists';
    protected $fillable = ['student_name', 'student_registration_id', 'date_of_join',    'student_phone_no', 'student_photo','date_of_completion','dob' ];

}

input in view

<div class="col-md-3">
<input   type="date" name="date_of_completion" class="form-control form-control-lg" id="date_of_completion"  required>
</div>

via Chebli Mohamed