XF 2.2 Import from vB 5.6.8 fails

[Dianin]

Trying to import vB 5.6.8, getting the fatal error:

ErrorException: [E_WARNING] Trying to access array offset on value of type int in src/addons/XFI/Import/Importer/vBulletin.php at line 3002

1. XF::handlePhpError() in src/addons/XFI/Import/Importer/vBulletin.php at line 3002
2. XFI\Import\Importer\vBulletin->stepThreads() in src/XF/Import/Runner.php at line 244
3. XF\Import\Runner->runStep() in src/XF/Import/Runner.php at line 61
4. XF\Import\Runner->run() in src/XF/Admin/Controller/Import.php at line 234
5. XF\Admin\Controller\Import->actionRun() in src/XF/Mvc/Dispatcher.php at line 352
6. XF\Mvc\Dispatcher->dispatchClass() in src/XF/Mvc/Dispatcher.php at line 259
7. XF\Mvc\Dispatcher->dispatchFromMatch() in src/XF/Mvc/Dispatcher.php at line 115
8. XF\Mvc\Dispatcher->dispatchLoop() in src/XF/Mvc/Dispatcher.php at line 57
9. XF\Mvc\Dispatcher->run() in src/XF/App.php at line 2352
10. XF\App->run() in src/XF.php at line 524
11. XF::runApp() in admin.php at line 13

The System:
MySQL 8.0.28
PHP 8.1.6
NginX 1.21.6
Fresh install of the XF 2.2.9 with XenForo Importers 1.5.1

Tried to import 'Forum with Blogs' and 'Forum only' with the same result.