Error if page has NULL slug

[Christian Toffolo]

Hi,
if a page for some reason (external import) has a NULL slug, this error happens on saving the page:
Argument 2 passed to Wazum\Sluggi\Backend\Service\SlugService::rebuildSlugsForSlugChange() must be of the type string, null given, called in /typo3conf/ext/sluggi/Classes/Backend/Hook/DataHandlerSlugUpdateHook.php on line 148

TYPO3 10 LTS
sluggi 2.0.3