Error: Call to a member function getFieldStorageDefinition() on null in Drupal\Core\Entity\ContentEntityBase->getEntityKey()

Problem/Motivation

When visiting an item "/order/item/1" the following error occurs

Error: Call to a member function getFieldStorageDefinition() on null in Drupal\Core\Entity\ContentEntityBase->getEntityKey() (line 1343 of \core\lib\Drupal\Core\Entity\ContentEntityBase.php).

Steps to reproduce

I use the drupal 10 version
https://git.drupalcode.org/project/order/-/tree/4a6634e5edefe8607f330bb6...

Drupal 10.3
PHP 8.1

Visit an order "/order/item/1"