Partner report:

In line 56 of this file vendor/ezsystems/recommendation-bundle/ez/publish/legacysearch/RecommendationLegacySearchEngine.php you can see that is does $this->recommendationClient->deleteContent($contentObjectId);

This is done by eZ when logging in connection with eZContentObject::cleanupAllInternalDrafts( $userID );
Now, the problem is that in that deleteContent() function it the again tries to fetch the object, which of-course is not published and therefor throws an error.

So this problem is only a problem for the users who have old drafts that should be deleted by the eZContentObject::cleanupAllInternalDrafts( $userID );