TYPO3 Core

After hours of debugging we discovered that there is an unwanted comma after "event.listener" in line 259 of /sysext/core/Configuration/Services.yaml

 - name: event.listener,
        identifier: 'legacy-slot'
        method: 'onReferenceIndexShouldExcludeTableFromReferenceIndexSignal'
        event: TYPO3\CMS\Core\DataHandling\Event\IsTableExcludedFromReferenceIndexEvent

This will break the YAML at this point. So the Signal won't be triggered. Even the Service itself won't be visible in Backend > Configuration > PSR-14