getEntityClass() must be of the type string, null returned

Problem/Motivation

After update I randomly get this error, but did not create any bundle classes. One time it loads the entity, other time it does not load the same entity. I will update issue as I understand more why this is happening.

TypeError: Return value of Drupal\Core\Entity\EntityStorageBase::getEntityClass() must be of the type string, null returned in Drupal\Core\Entity\EntityStorageBase->getEntityClass() (line 115 of /web/core/lib/Drupal/Core/Entity/EntityStorageBase.php)
#0 /web/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php(196): Drupal\Core\Entity\EntityStorageBase->getEntityClass()
#1 /web/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php(508): Drupal\Core\Entity\ContentEntityStorageBase->getEntityClass()
#2 /web/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php(427): Drupal\Core\Entity\Sql\SqlContentEntityStorage->mapFromStorageRecords()
#3 /web/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php(393): Drupal\Core\Entity\Sql\SqlContentEntityStorage->getFromStorage()
#4 /web/core/lib/Drupal/Core/Entity/EntityStorageBase.php(346): Drupal\Core\Entity\Sql\SqlContentEntityStorage->doLoadMultiple()
#5 /web/core/lib/Drupal/Core/Entity/EntityStorageBase.php(296): Drupal\Core\Entity\EntityStorageBase->loadMultiple()
#6 ...: Drupal\Core\Entity\EntityStorageBase->load()

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet