Reindexing doesn't index node titles

Upon investigation of a batch reindex, it was discovered that user data is the only data that seems to be indexed.
Steps to reproduce

1. Create 3 nodes test1, test2, test10
2. create 3 users test1,test2, test10
3. enable views natural sort
4. run drush sqlq "select * from views_natural_sort"

Expected result
Node titles should be in there.

Original Title

Doesn't work with PHP 7.3

Original Summary

I installed this module and tried to index but get this
Notice: unserialize(): Error at offset 23011 of 39168 bytes in Drupal\Core\Batch\BatchStorage->load() (line 71 of core/lib/Drupal/Core/Batch/BatchStorage.php).
Drupal\Core\Batch\BatchStorage->load('1269') (Line: 75)
Drupal\Core\ProxyClass\Batch\BatchStorage->load('1269') (Line: 43)
_batch_page(Object) (Line: 55)
Drupal\system\Controller\BatchController->batchPage(Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 151)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 50)
Drupal\ban\BanMiddleware->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 708)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

Making the module unusable because it does not sort.