Error: Class name must be a valid object or a string

[Tagra]

Hello,
When i am using code as below i am getting this error: "Class name must be a valid object or a string"
NovaBelongsToDepend::make('Class', 'VehicleClass', \App\Nova\Vehicle\VehicleClass::class)

But with default BelongsTo
BelongsTo::make('Class', 'VehicleClass', \App\Nova\Vehicle\VehicleClass::class)

It works just fine, what can cause a problem ?

[Tagra]

Not sure what is the problem but it works perfect when i uncomment
$this->value = $this->formatDisplayValue($value);

$value = $resource->{$this->attribute}()->withoutGlobalScopes()->first();
if ($value) {
$this->valueKey = $value->getKey();
//$this->value = $this->formatDisplayValue($value);
}