json_decode(): Passing null to parameter #1 ($json) of type string is deprecated

[Guanch1]

It puts proper json records to database but not showing and not saving in nova preview.

Multiselect::make('Особенности', 'features')
                ->options([
                    'terrace' => 'Терраса',
                    'communal-pool' => 'Общий бассейн',

i try ->saveAsJSON()
but only fixed by

->resolveUsing(function ($value) {
                    return empty($value) ? [] : $value;
                })
                ->fillUsing(function ($request, $model, $attribute, $requestAttribute) {
                    $value = $request->input($attribute);
                    if (is_null($value)) {
                        $model->{$attribute} = '[]';
                    } else {
                        $model->{$attribute} = is_string($value) ? $value : json_encode($value);
                    }
                })

Now working for me but still got warnings.