Unable to process Batch actions as Administrator

I'm working with a brand new install of Drupal 10 and am having issues with the administrator account (both the default one created at startup and my own personal account) having 'Access Denied' errors when attempting to perform Batch operations. This is specifically linked to attempts to batch delete users at the moment, but I likely have other issues with Batch actions as these commands are not currently being processed.

What I've tried so far:

1. Clearing the cache from the web side of the application.
2. Rebuilding the node permissions on the web side of the application.
3. Re-building the cache from drush on the server.
4. Making sure the user accounts are in the administrator group using drush.
5. Re-creating the node permissions using drush and eval().

The site logs contain only the following in the logged error message denying access to Batch:

Path: /batch?id=13&op=start. Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException: in Drupal\system\Controller\BatchController->batchPage() (line 55 of /srv/advita-marketing/web/core/modules/system/src/Controller/BatchController.php).

The Batch information is being correctly created in the database.

I'm not currently using any third-party modules that affect permissions. The install is 99% vanilla Drupal at the moment.

I've checked Permissions under the People page and permissions for Administrator to perform the actions I'm expecting it to are checked as being active permissions.

I also have ruled out .htaccess as being a cause of the error as I'm running the application on Nginx.

Any help here would be appreciated.