Problem modifying existing entity with enum and saving it

[kaihoefler]

Hi,
I'm sorry but I have another problem after migration my application which uses Enum form Cake 3 to Cake 5:

I have an Entity e.g. Article which contains an enum attribute visibility.
The enum is defined as follows:

$this->addBehavior('CakeDC/Enum.Enum', ['lists' => [ 'visibility' => [ 'strategy' => 'const', 'prefix' => 'VISIBILITY', 'field' => 'visibility', 'translate' => true ] ]]);

When I read an existing entity and modify it in the controller,

$article = $this->Articles->get($id); $article->count_viewed = $article->count_viewed + 1; $this->Articles->save($article));

the save operation is throwing a TypeError

"array_key_exists(): Argument #1 ($key) must be a valid array offset type"
in ROOT/vendor/cakedc/enum/src/Model/Behavior/EnumBehavior.php at line 299

As far as I see the problem originates by the fact that after reading the visibility attribute is an object(Cake\ORM\Entity) but when I save the value a string is expected.
Because after

$article->visibility = $article->visibility->value;

saving ist possible.