Cascade delete TYPO3 inline records don't work
Solution 1:
enableCascadingDelete has no effect on MM related tables. In \TYPO3\CMS\Core\DataHandling\DataHandler->deleteRecord_procBasedOnFieldType the inline type is checked and only if it's of type field (foreign_field must be set in the TCA) or list (MM and foreign_field must not be set in TCA) child entries will be deleted.