With analysing the runtime of commands, I was able to identify the position where the starting-point of this problem is. The call-sequence to the starting-point is:
...->image()->crop(...)traits/image.php:-
public function crop()-> public function thumb(): return $this->kirby->component('thumb')->create($this, $params);component/thumb.php:public function create(): $thumb = new Generator($file, $params);toolkit/lib/thumb.php:-
public function __construct(): $this->destination = $this->destination();-> public function destination(): $result = call($this->options['destination'], $this);toolkit/helpers.php:function call(): call_user_func_array($function, $arguments)
And exactly the call of call_user_func_array($function, $arguments) causes this problem.