Getting notice

Notice: Undefined index: input in Drupal\if_then_else\core\Nodes\Actions\BooleanNotAction\BooleanNotAction->process() (line 51 of modules/contrib/if_then_else/src/core/Nodes/Actions/BooleanNotAction/BooleanNotAction.php).
Drupal\if_then_else\core\Nodes\Actions\BooleanNotAction\BooleanNotAction->process() (Line: 110)
Drupal\if_then_else\Controller\IfThenElseController::process('after_saving_existing_entity_event', Array) (Line: 164)
if_then_else_entity_update(Object)
call_user_func_array('if_then_else_entity_update', Array) (Line: 403)
Drupal\Core\Extension\ModuleHandler->invokeAll('entity_update', Array) (Line: 206)
Drupal\Core\Entity\EntityStorageBase->invokeHook('update', Object) (Line: 835)
Drupal\Core\Entity\ContentEntityStorageBase->invokeHook('update', Object) (Line: 527)
Drupal\Core\Entity\EntityStorageBase->doPostSave(Object, 1) (Line: 720)
Drupal\Core\Entity\ContentEntityStorageBase->doPostSave(Object, 1) (Line: 452)
Drupal\Core\Entity\EntityStorageBase->save(Object) (Line: 838)
Drupal\Core\Entity\Sql\SqlContentEntityStorage->save(Object) (Line: 394)
Drupal\Core\Entity\EntityBase->save() (Line: 293)
Drupal\node\NodeForm->save(Array, Object)
call_user_func_array(Array, Array) (Line: 111)
Drupal\Core\Form\FormSubmitter->executeSubmitHandlers(Array, Object) (Line: 51)
Drupal\Core\Form\FormSubmitter->doSubmitForm(Array, Object) (Line: 590)
Drupal\Core\Form\FormBuilder->processForm('node_page_edit_form', Array, Object) (Line: 319)
Drupal\Core\Form\FormBuilder->buildForm('node_page_edit_form', Object) (Line: 93)
Drupal\Core\Controller\FormController->getContentResult(Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 582)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 151)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
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: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 45)
Drupal\jsonapi\StackMiddleware\FormatSetter->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 693)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)