Critical issues with 8.1 core

Do not install with Drupal 8.1 core version.

Error: Class name must be a valid object or a string in /var/www/vagrant/docroot/core/modules/field/src/FieldStorageConfigStorage.php on line 155
Error: Class name must be a valid object or a string in Drupal\field\FieldStorageConfigStorage->mapFromStorageRecords() (line 155 of /var/www/vagrant/docroot/core/modules/field/src/FieldStorageConfigStorage.php).

The module does not install correctly, cannot be uninstalled, caches can't be cleared, the entire Drupal instance is now defect.

The website encountered an unexpected error. Please try again later.
Error: Class name must be a valid object or a string in Drupal\field\FieldStorageConfigStorage->mapFromStorageRecords() (line 155 of core/modules/field/src/FieldStorageConfigStorage.php).
Drupal\field\FieldStorageConfigStorage->mapFromStorageRecords(Array, Array) (Line: 189)
Drupal\Core\Config\Entity\ConfigEntityStorage->doLoadMultiple(Array) (Line: 242)
Drupal\Core\Entity\EntityStorageBase->loadMultiple(Array) (Line: 501)
Drupal\Core\Entity\Entity::loadMultiple(Array) (Line: 180)
field_entity_field_storage_info(Object)
call_user_func_array('field_entity_field_storage_info', Array) (Line: 391)
Drupal\Core\Extension\ModuleHandler->invoke('field', 'entity_field_storage_info', Array) (Line: 510)
Drupal\Core\Entity\EntityFieldManager->buildFieldStorageDefinitions('node') (Line: 406)
Drupal\Core\Entity\EntityFieldManager->getFieldStorageDefinitions('node') (Line: 152)
Drupal\Core\Entity\EntityManager->getFieldStorageDefinitions('node') (Line: 284)
Drupal\field\Entity\FieldConfig->getFieldStorageDefinition() (Line: 336)
Drupal\Core\Field\FieldConfigBase->getSettings() (Line: 517)
Drupal\Core\Field\FieldConfigBase->getItemDefinition() (Line: 369)
Drupal\search_api\Utility::getInnerProperty(Object) (Line: 343)
Drupal\search_api\Utility::retrieveNestedProperty(Array, 'body') (Line: 396)
Drupal\search_api\Item\Field->getDataDefinition() (Line: 176)
_search_api_views_get_handlers(Object) (Line: 56)
search_api_views_data()
call_user_func_array('search_api_views_data', Array) (Line: 391)
Drupal\Core\Extension\ModuleHandler->invoke('search_api', 'views_data') (Line: 232)
Drupal\views\ViewsData->getData() (Line: 135)
Drupal\views\ViewsData->get('node__field_weight') (Line: 85)
Drupal\views\Plugin\ViewsHandlerManager->getHandler(Array, NULL) (Line: 882)
Drupal\views\Plugin\views\display\DisplayPluginBase->getHandlers('sort') (Line: 1030)
Drupal\views\ViewExecutable->_initHandler('sort', Array) (Line: 888)
Drupal\views\ViewExecutable->initHandlers() (Line: 2255)
Drupal\views\Plugin\views\display\DisplayPluginBase->preExecute() (Line: 1677)
Drupal\views\ViewExecutable->preExecute(Array) (Line: 1612)
Drupal\views\ViewExecutable->executeDisplay('page_1', Array) (Line: 78)
Drupal\views\Element\View::preRenderViewElement(Array)
call_user_func(Array, Array) (Line: 381)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array, ) (Line: 226)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 574)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 227)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 117)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object) (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.view', Object) (Line: 149)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 64)
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: 98)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 77)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 50)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 628)
Drupal\Core\DrupalKernel->handle(Object) (Line: 23)