Version 5.0.6

applications/core/modules/admin/settings/webapp.php

@@ -147,7 +147,7 @@ class webapp extends Controller
 		if( $values = $form->values() )
 		{
 			$path = Url::createFromString( Url::baseUrl() )->data[ Url::COMPONENT_PATH ];
-			$startUrl = $path ?? '';
+			$startUrl = !empty( $path ) ? $path : '/';
 
 			if ( $values['manifest_custom_url_toggle'] !== FALSE and ! empty( $values['manifest_short_url'] ) )
 			{