Circular reference detected for service "business_rules.processor"

I have encountered the same issue, the attached patch fixes it for me. Although the patch is logically correct as it prevents `hook_entity_load()` from running on non content entities (like form modes), I think the actual root cause for the circular reference should also be resolved.

Steps to reproduce:

1. Clear the plugin cache drush cc plugin.
2. Visit any page.
3. hook_entity_type_alter() will get invoked and will reach to a point where hook_entity_load() is invoked as well, resulting in the mentioned error.

Full stack trace:

The website encountered an unexpected error. Please try again later.

Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException: Circular reference detected for service "business_rules.processor", path: "business_rules.event_listener -> business_rules.processor -> business_rules.util -> eca.service.token -> eca.token_data.current_user". in Drupal\Component\DependencyInjection\Container->get() (line 146 of core/lib/Drupal/Component/DependencyInjection/Container.php).
Drupal::service('business_rules.processor') (Line: 347)
business_rules_entity_load(Array, 'entity_form_mode') (Line: 431)
Drupal\Core\Entity\EntityStorageBase->Drupal\Core\Entity\{closure}(Object, 'business_rules') (Line: 405)
Drupal\Core\Extension\ModuleHandler->invokeAllWith('entity_load', Object) (Line: 432)
Drupal\Core\Entity\EntityStorageBase->postLoad(Array) (Line: 353)
Drupal\Core\Entity\EntityStorageBase->loadMultiple() (Line: 114)
Drupal\Core\Entity\EntityDisplayRepository->getAllDisplayModesByEntityType('form_mode') (Line: 85)
Drupal\Core\Entity\EntityDisplayRepository->getAllFormModes() (Line: 516)
business_rules_entity_type_alter(Array, NULL, NULL) (Line: 562)
Drupal\Core\Extension\ModuleHandler->alter('entity_type', Array) (Line: 334)
Drupal\Core\Plugin\DefaultPluginManager->alterDefinitions(Array) (Line: 123)
Drupal\Core\Entity\EntityTypeManager->findDefinitions() (Line: 175)
Drupal\Core\Plugin\DefaultPluginManager->getDefinitions() (Line: 22)
Drupal\Core\Plugin\DefaultPluginManager->getDefinition('user', ) (Line: 132)
Drupal\Core\Entity\EntityTypeManager->getDefinition('user') (Line: 253)
Drupal\Core\Entity\EntityTypeManager->getHandler('user', 'storage') (Line: 192)
Drupal\Core\Entity\EntityTypeManager->getStorage('user') (Line: 41)
Drupal\eca\Token\CurrentUserDataProvider->__construct(Object, Object) (Line: 262)
Drupal\Component\DependencyInjection\Container->createService(Array, 'eca.token_data.current_user') (Line: 176)
Drupal\Component\DependencyInjection\Container->get('eca.token_data.current_user', 1) (Line: 437)
Drupal\Component\DependencyInjection\Container->resolveServicesAndParameters(Array) (Line: 276)
Drupal\Component\DependencyInjection\Container->createService(Array, 'eca.service.token') (Line: 176)
Drupal\Component\DependencyInjection\Container->get('eca.service.token') (Line: 176)
Drupal\business_rules\Util\BusinessRulesUtil->__construct(Object) (Line: 262)
Drupal\Component\DependencyInjection\Container->createService(Array, 'business_rules.util') (Line: 176)
Drupal\Component\DependencyInjection\Container->get('business_rules.util') (Line: 159)
Drupal\business_rules\Util\BusinessRulesProcessor->__construct(Object) (Line: 262)
Drupal\Component\DependencyInjection\Container->createService(Array, 'business_rules.processor') (Line: 176)
Drupal\Component\DependencyInjection\Container->get('business_rules.processor', 1) (Line: 437)
Drupal\Component\DependencyInjection\Container->resolveServicesAndParameters(Array) (Line: 240)
Drupal\Component\DependencyInjection\Container->createService(Array, 'business_rules.event_listener') (Line: 176)
Drupal\Component\DependencyInjection\Container->get('business_rules.event_listener') (Line: 136)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, Object) (Line: 52)
Drupal\business_rules\EventSubscriber\KernelRequestListener->onKernelRequest(Object, 'kernel.request', Object)
call_user_func(Array, Object, 'kernel.request', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.request') (Line: 135)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
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: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 709)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

Please ignore the patch in #2.

Patch #3 fixed issue for me

I am also seeing this issue. It happens whenever another module has been un-installed, but before caches have been rebuilt.