TypeError: Argument 1 passed line 306

Problem/Motivation

I'm trying to place a webform block into a sidebar. Doing so breaks the page layout.
The only way to recover from the break is to completely uninstall the webform modules.

I reset my site to the Bartik theme in case it was custom-theme related but the error is the same.

Steps to reproduce

I'm on Drupal 9.1.0 and have installed via composer:
Webform 6.0.0-Beta3 with webform bootstrap, webform node, Webform Submission Export/Import, Webform Submission Log, Webform Templates, Webform UI.

I've created a form with first & last name plain text fields then tried to add the block to the sidebar

The error message I get is:
The website encountered an unexpected error. Please try again later.
TypeError: Argument 1 passed to Drupal\webform\WebformEntityReferenceManager::getParagraphWebformsRecursive() must implement interface Drupal\Core\Entity\EntityInterface, null given, called in /app/modules/contrib/webform/src/WebformEntityReferenceManager.php on line 306 in Drupal\webform\WebformEntityReferenceManager->getParagraphWebformsRecursive() (line 281 of modules/contrib/webform/src/WebformEntityReferenceManager.php).

Drupal\webform\WebformEntityReferenceManager->getParagraphWebformsRecursive(NULL, Array, Array) (Line: 306)
Drupal\webform\WebformEntityReferenceManager->getParagraphWebformsRecursive(Object, Array, Array) (Line: 249)
Drupal\webform\WebformEntityReferenceManager->getWebforms(Object) (Line: 219)
Drupal\webform\WebformEntityReferenceManager->getWebform(Object) (Line: 184)
Drupal\webform_node\Access\WebformNodeAccess::checkAccess('webform_submission_view', 'webform.test', Object, NULL, Object) (Line: 120)
Drupal\webform_node\Access\WebformNodeAccess::checkWebformAccess('webform_submission_view', 'webform.test', Object, Object)
call_user_func_array(Array, Array) (Line: 75)
Drupal\Core\Access\CustomAccessCheck->access(Object, Object, Object)
call_user_func_array(Array, Array) (Line: 159)
Drupal\Core\Access\AccessManager->performCheck('access_check.custom', Object) (Line: 135)
Drupal\Core\Access\AccessManager->check(Object, Object, NULL, 1) (Line: 92)
Drupal\Core\Access\AccessManager->checkNamedRoute('entity.node.webform.test_form', Array, Object, 1) (Line: 327)
Drupal\Core\Menu\LocalTaskManager->getTasksBuild('entity.node.canonical', Object) (Line: 358)
Drupal\Core\Menu\LocalTaskManager->getLocalTasks('entity.node.canonical', 0) (Line: 95)
Drupal\Core\Menu\Plugin\Block\LocalTasksBlock->build() (Line: 171)
Drupal\block\BlockViewBuilder::preRender(Array)
call_user_func_array(Array, Array) (Line: 101)
Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. See https://www.drupal.org/node/2966725', 'exception', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 781)
Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 372)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 444)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 200)
Drupal\Core\Render\Renderer->render(Array) (Line: 450)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 97)
__TwigTemplate_bbec8ec001c823d13f100da986ad02069eae723bf17d9a6a775d945ce9315f1e->doDisplay(Array, Array) (Line: 405)
Twig\Template->displayWithErrorHandling(Array, Array) (Line: 378)
Twig\Template->display(Array) (Line: 390)
Twig\Template->render(Array) (Line: 65)
twig_render_template('core/themes/bartik/templates/page.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('page', Array) (Line: 431)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 200)
Drupal\Core\Render\Renderer->render(Array) (Line: 450)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 86)
__TwigTemplate_e3ce77d699b2d0424af4a71854f1a83103acebb13ebd2caa21f76e1d8e926c7e->doDisplay(Array, Array) (Line: 405)
Twig\Template->displayWithErrorHandling(Array, Array) (Line: 378)
Twig\Template->display(Array) (Line: 390)
Twig\Template->render(Array) (Line: 65)
twig_render_template('core/themes/bartik/templates/classy/layout/html.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('html', Array) (Line: 431)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 200)
Drupal\Core\Render\Renderer->render(Array) (Line: 162)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 163)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
call_user_func(Array, Object, 'kernel.view', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.view') (Line: 163)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 80)
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: 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: 706)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

Please let me know if there is anything I can try or test. I don't know what I should do to fix this.
Thanks!