Error running update.php from 8.x-5.0-beta4

Installed the 8x-5.x-dev version on dev version of site today - I'd like to use the conditional e-mail feature.
Updated from version 8.x-5.0-beta4. Running update.php yields the following error (+stack trace):

( ! ) Fatal error: Cannot use Drupal\webform\Entity\Webform as Webform because the name is already in use in ...\modules\webform\src\Element\WebformExcludedColumns.php on line 5
Call Stack
# Time Memory Function Location
1 0.0000 141736 {main}( ) ...\update.php:0
2 0.0781 1069544 Drupal\Core\Update\UpdateKernel->handle( ) ...\update.php:19
3 13.0781 17181768 Drupal\Core\Update\UpdateKernel->handleRaw( ) ...\UpdateKernel.php:73
4 13.3906 17922616 call_user_func_array:{...\core\lib\Drupal\Core\Update\UpdateKernel.php:110} ( ) ...\UpdateKernel.php:110
5 13.3906 17923048 Drupal\system\Controller\DbUpdateController->handle( ) ...\UpdateKernel.php:110
6 15.0312 20103296 Drupal\Core\ProxyClass\Render\BareHtmlPageRenderer->renderBarePage( ) ...\DbUpdateController.php:196
7 15.2031 20792896 Drupal\Core\Render\BareHtmlPageRenderer->renderBarePage( ) ...\BareHtmlPageRenderer.php:76
8 15.2812 21296520 Drupal\Core\Render\Renderer->renderRoot( ) ...\BareHtmlPageRenderer.php:66
9 15.2812 21307544 Drupal\Core\Render\Renderer->executeInRenderContext( ) ...\Renderer.php:140
10 15.2812 21307792 Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}( ) ...\Renderer.php:574
11 15.2812 21307856 Drupal\Core\Render\Renderer->render( ) ...\Renderer.php:139
12 15.2812 21308576 Drupal\Core\Render\Renderer->doRender( ) ...\Renderer.php:195
13 15.2812 21309176 Drupal\Core\Render\ElementInfoManager->getInfo( ) ...\Renderer.php:298
14 15.2812 21309304 Drupal\Core\Render\ElementInfoManager->buildInfo( ) ...\ElementInfoManager.php:76
15 15.4844 22572328 Drupal\Core\Render\ElementInfoManager->createInstance( ) ...\ElementInfoManager.php:110
16 15.4844 22572408 Drupal\Component\Plugin\PluginManagerBase->createInstance( ) ...\ElementInfoManager.php:140
17 15.4844 22572408 Drupal\Core\Plugin\Factory\ContainerFactory->createInstance( ) ...\PluginManagerBase.php:84
18 15.4844 22572408 Drupal\Component\Plugin\Factory\DefaultFactory::getPluginClass( ) ...\ContainerFactory.php:17
19 15.4844 22572720 class_exists ( ) ...\DefaultFactory.php:96
20 15.4844 22572952 spl_autoload_call ( ) ...\DefaultFactory.php:96
21 15.4844 22573008 Composer\Autoload\ClassLoader->loadClass( ) ...\DefaultFactory.php:96
22 15.4844 22573152 Composer\Autoload\includeFile( )

Screenshot here