Laravel Backpack attribute accessor causing bug on update command - laravel-backpack

Question

I am working on Laravel Backpack. I have two fields like this:
$this->crud->addField([ // SELECT2
'label' => 'Type',
'type' => 'select_from_array',
'name' => 'type',
'options' => [
'' => 'select type',
'Movie' => 'Movies',
'Series' => 'Series'
],
]);
$this->crud->addField([ // select2_from_ajax: 1-n relationship
'label' => "Entity", // Table column heading
'type' => 'select2_from_ajax',
'name' => 'entity_id', // the column that contains the ID of that connected entity;
'entity' => 'entity', // the method that defines the relationship in your Model
'attribute' => 'name', // foreign key attribute that is shown to user
'data_source' => url('api/entity'), // url to controller search function (with /{id} should return model)
'placeholder' => 'Select', // placeholder for the select
'include_all_form_fields' => true, //sends the other form fields along with the request so it can be filtered.
'minimum_input_length' => 0, // minimum characters to type before querying results
'dependencies' => ['type'], // when a dependency changes, this select2 is reset to null
// 'method' => 'GET', // optional - HTTP method to use for the AJAX call (GET, POST)
]);
The second field options are dependent on the first one.
In my model, I have:
public function getEntityIdAttribute()
{
$id = $this->attributes['entity_id'];
$type = $this->attributes['type'];
if ($type == "Movie") {
$attribute = Movie::find($id);
} else {
$attribute = Series::find($id);
}
return $attribute->name;
}
Create and List operations work perfectly. But on update, it throws this error:
Undefined array key "entity_id"
Why is this accessor not working on the update? or can we somehow skip the accessor on the update command?