Undefined array key error

Additional information:

I started thinking about the error having to do with Taxonomy. We are using "Departments" as a Taxonomy vocabulary in Workbench Access. In the Departments taxonomy, there is hierarchy. I wonder if this module has an issue with figuring out hierarchy for taxonomy? This is as far as I've gone with that line of reasoning.

This (I think) is a change to how field settings are stored in Drupal 8 and 9,

The problem is right here in lines 113-117, in that $handler_settings might not be set, so !empty fails on later versions of PHP.

      $bundles = $this->entityTypeBundleInfo->getBundleInfo('taxonomy_term');
      if (isset($this->configuration['handler_settings'])) {
        $handler_settings = $this->configuration['handler_settings'];
      }
      $bundle_names = !empty($handler_settings['target_bundles']) ? $handler_settings['target_bundles'] : array_keys($bundles);

Committed.

Automatically closed - issue fixed for 2 weeks with no activity.