Undefined index: #entity_type error

I've used this module with success in the past, but in my drupal 8.5.6 site, using Formatter settings for either Background Image or Responsive Background Image, nothing shows up. In my log I see the following error:

Notice: Undefined index: #entity_type in Drupal\bg_image_formatter\Plugin\Field\FieldFormatter\BgImageFormatter->settingsForm() (line 190 of /home/ubuntu/workspace/web/modules/contrib/bg_image_formatter/src/Plugin/Field/FieldFormatter/BgImageFormatter.php) #0 /home/ubuntu/workspace/web/core/includes/bootstrap.inc(582): _drupal_error_handler_real(8, 'Undefined index...', '/home/ubuntu/wo...', 190, Array) #1 /home/ubuntu/workspace/web/modules/contrib/bg_image_formatter/src/Plugin/Field/FieldFormatter/BgImageFormatter.php(190): _drupal_error_handler(8, 'Undefined index...', '/home/ubuntu/wo...', 190, Array) #2 /home/ubuntu/workspace/web/modules/contrib/bg_image_formatter/modules/responsive_bg_image_formatter/src/Plugin/Field/FieldFormatter/ResponsiveBgImageFormatter.php(27): Drupal\bg_image_formatter\Plugin\Field\FieldFormatter\BgImageFormatter->settingsForm(Array, Object(Drupal\Core\Form\FormState)) #3 /home/ubuntu/workspace/web/core/modules/views/src/Plugin/views/field/EntityField.php(485): Drupal\responsive_bg_image_formatter\Plugin\Field\FieldFormatter\ResponsiveBgImageFormatter->settingsForm(Array, Object(Drupal\Core\Form\FormState)) #4 /home/ubuntu/workspace/web/core/modules/views_ui/src/Form/Ajax/ConfigHandler.php(167): Drupal\views\Plugin\views\field\EntityField->buildOptionsForm(Array, Object(Drupal\Core\Form\FormState)) #5 [internal function]: Drupal\views_ui\Form\Ajax\ConfigHandler->buildForm(Array, Object(Drupal\Core\Form\FormState)) #6 /home/ubuntu/workspace/web/core/lib/Drupal/Core/Form/FormBuilder.php(518): call_user_func_array(Array, Array) #7 /home/ubuntu/workspace/web/core/lib/Drupal/Core/Form/FormBuilder.php(275): Drupal\Core\Form\FormBuilder->retrieveForm('views_ui_config...', Object(Drupal\Core\Form\FormState)) #8 /home/ubuntu/workspace/web/core/modules/views_ui/src/Form/Ajax/ViewsFormBase.php(214): Drupal\Core\Form\FormBuilder->buildForm('views_ui_config...', Object(Drupal\Core\Form\FormState)) #9 /home/ubuntu/workspace/web/core/lib/Drupal/Core/Render/Renderer.php(582): Drupal\views_ui\Form\Ajax\ViewsFormBase->Drupal\views_ui\Form\Ajax\{closure}() #10 /home/ubuntu/workspace/web/core/modules/views_ui/src/Form/Ajax/ViewsFormBase.php(216): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #11 /home/ubuntu/workspace/web/core/modules/views_ui/src/Form/Ajax/ViewsFormBase.php(125): Drupal\views_ui\Form\Ajax\ViewsFormBase->ajaxFormWrapper('Drupal\\views_ui...', Object(Drupal\Core\Form\FormState)) #12 /home/ubuntu/workspace/web/core/modules/views_ui/src/Form/Ajax/ConfigHandler.php(39): Drupal\views_ui\Form\Ajax\ViewsFormBase->getForm(Object(Drupal\views_ui\ViewUI), 'block_1', 'ajax') #13 [internal function]: Drupal\views_ui\Form\Ajax\ConfigHandler->getForm(Object(Drupal\views_ui\ViewUI), 'block_1', 'ajax', 'field', 'field_image') #14 /home/ubuntu/workspace/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array) #15 /home/ubuntu/workspace/web/core/lib/Drupal/Core/Render/Renderer.php(582): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #16 /home/ubuntu/workspace/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #17 /home/ubuntu/workspace/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) #18 /home/ubuntu/workspace/vendor/symfony/http-kernel/HttpKernel.php(151): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #19 /home/ubuntu/workspace/vendor/symfony/http-kernel/HttpKernel.php(68): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #20 /home/ubuntu/workspace/web/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #21 /home/ubuntu/workspace/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #22 /home/ubuntu/workspace/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(99): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #23 /home/ubuntu/workspace/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(78): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #24 /home/ubuntu/workspace/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #25 /home/ubuntu/workspace/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #26 /home/ubuntu/workspace/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #27 /home/ubuntu/workspace/web/core/lib/Drupal/Core/DrupalKernel.php(666): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #28 /home/ubuntu/workspace/web/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #29 {main}.