PHP Notice causing memcache statistics page to fail

Stack trace:

php.NOTICE: Notice: A non well formed numeric value encountered in Drupal\memcache\Driver\DriverBase->stats() (line 208 of /var/www/html/docroot/modules/contrib/memcache/src/Driver/DriverBase.php) #0 /var/www/html/docroot/core/includes/bootstrap.inc(600): _drupal_error_handler_real(8, 'A non well form...', '/var/www/html/d...', 208, Array) #1 /var/www/html/docroot/modules/contrib/memcache/src/Driver/DriverBase.php(208): _drupal_error_handler(8, 'A non well form...', '/var/www/html/d...', 208, Array) #2 /var/www/html/docroot/modules/contrib/memcache/memcache_admin/src/Controller/MemcacheStatisticsController.php(33): Drupal\memcache\Driver\DriverBase->stats('cache', 'default', true) #3 [internal function]: Drupal\memcache_admin\Controller\MemcacheStatisticsController->statsTable('cache') #4 /var/www/html/docroot/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array) #5 /var/www/html/docroot/core/lib/Drupal/Core/Render/Renderer.php(573): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #6 /var/www/html/docroot/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #7 /var/www/html/docroot/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) #8 /var/www/html/vendor/symfony/http-kernel/HttpKernel.php(151): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #9 /var/www/html/vendor/symfony/http-kernel/HttpKernel.php(68): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #10 /var/www/html/docroot/modules/contrib/simple_oauth/src/HttpMiddleware/BasicAuthSwap.php(67): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #11 /var/www/html/docroot/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Drupal\simple_oauth\HttpMiddleware\BasicAuthSwap->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #12 /var/www/html/docroot/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #13 /var/www/html/docroot/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #14 /var/www/html/docroot/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #15 /var/www/html/docroot/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #16 /var/www/html/docroot/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #17 /var/www/html/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #18 /var/www/html/docroot/core/lib/Drupal/Core/DrupalKernel.php(708): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #19 /var/www/html/docroot/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #20 {main}.
{
"severity_level": 5
}

This was caused by the stats bin for a server containing a string for the stats variable keyed by 'libevent'. Since this shouldn't be aggregated, I added 'libevent' to the 'no aggregate' array.