When you try to batch edit a column which is a relationship field that also has a pathformatter it will show an error after selecting a new value.

Message: Argument 1 passed to Pimcore\Bundle\AdminBundle\Controller\Admin\ElementController::convertResultWithPathFormatter() must be an instance of Pimcore\Model\DataObject\Concrete, instance of Pimcore\Model\DataObject\Folder given, called in /var/www/html/vendor/pimcore/pimcore/bundles/AdminBundle/Controller/Admin/ElementController.php on line 494
Trace:
in /var/www/html/vendor/pimcore/pimcore/bundles/AdminBundle/Controller/Admin/ElementController.php:793
#0 /var/www/html/vendor/pimcore/pimcore/bundles/AdminBundle/Controller/Admin/ElementController.php(494): Pimcore\Bundle\AdminBundle\Controller\Admin\ElementController->convertResultWithPathFormatter(Object(Pimcore\Model\DataObject\Folder), Array, Array, Array)
#1 /var/www/html/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/HttpKernel.php(146): Pimcore\Bundle\AdminBundle\Controller\Admin\ElementController->getNicePathAction(Object(Symfony\Component\HttpFoundation\Request))
#2 /var/www/html/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/HttpKernel.php(68): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1)
#3 /var/www/html/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/Kernel.php(201): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#4 /var/www/html/web/app.php(36): Symfony\Component\HttpKernel\Kernel->handle(Object(Symfony\Component\HttpFoundation\Request))
#5 {main}

source: {"type":"object","id":2}
targets: {"object_4":{"id":4,"type":"object","subtype":"object","nicePathKey":"object_4"}}
context: {"containerType":"batch","fieldname":null}
loadEditModeData:
idProperty: nicePathKey

ID 2 is the id of the folder instead of the object. This seems to cause the issue.