Mautic 3.2.1 generates PHP errors during broadcast emails

We updated to 3.2.1. It was working fine previously, now the email broadcast breaks. We enter:

/public_html/bin/console mautic:broadcasts:send --limit=4000 --batch=4000 -v

We get back:
PHP Warning: include(/home/c2gunstuff/public_html/vendor/monolog/monolog/src/Monolog/Utils.php): failed to open stream: Too many open files in /home/c2gunstuff/public_html/vendor/composer/ClassLoader.php on line 444
PHP Warning: include(): Failed opening ‘/home/c2gunstuff/public_html/vendor/composer/…/monolog/monolog/src/Monolog/Utils.php’ for inclusion (include_path=’.:/opt/cpanel/ea-php73/root/usr/share/pear’) in /home/c2gunstuff/public_html/vendor/composer/ClassLoader.php on line 444

Over and over again until the script dies:
In NormalizerFormatter.php line 174:

[Symfony\Component\Debug\Exception\ClassNotFoundException]
Attempted to load class “Utils” from namespace “Monolog”.
Did you forget a “use” statement for e.g. “Monolog\Utils” or “JmesPath\Utils”?

Exception trace:
at /home/c2gunstuff/public_html/vendor/monolog/monolog/src/Monolog/Formatter/NormalizerFormatter.php:174
Monolog\Formatter\NormalizerFormatter->toJson() at /home/c2gunstuff/public_html/vendor/monolog/monolog/src/Monolog/Formatter/LineFormatter.php:163
Monolog\Formatter\LineFormatter->convertToString() at /home/c2gunstuff/public_html/vendor/monolog/monolog/src/Monolog/Formatter/LineFormatter.php:127
Monolog\Formatter\LineFormatter->stringify() at /home/c2gunstuff/public_html/vendor/monolog/monolog/src/Monolog/Formatter/LineFormatter.php:103
Monolog\Formatter\LineFormatter->format() at /home/c2gunstuff/public_html/vendor/monolog/monolog/src/Monolog/Handler/AbstractProcessingHandler.php:37
Monolog\Handler\AbstractProcessingHandler->handle() at /home/c2gunstuff/public_html/vendor/monolog/monolog/src/Monolog/Logger.php:344
Monolog\Logger->addRecord() at /home/c2gunstuff/public_html/vendor/monolog/monolog/src/Monolog/Logger.php:712
Monolog\Logger->error() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Swiftmailer/Transport/AmazonApiTransport.php:289
Mautic\EmailBundle\Swiftmailer\Transport\AmazonApiTransport->triggerSendError() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Swiftmailer/Transport/AmazonApiTransport.php:269
Mautic\EmailBundle\Swiftmailer\Transport\AmazonApiTransport->Mautic\EmailBundle\Swiftmailer\Transport{closure}() at n/a:n/a
call_user_func() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/EachPromise.php:166
GuzzleHttp\Promise\EachPromise->GuzzleHttp\Promise{closure}() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:203
GuzzleHttp\Promise\Promise::callHandler() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:174
GuzzleHttp\Promise\Promise::GuzzleHttp\Promise{closure}() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/RejectedPromise.php:40
GuzzleHttp\Promise\RejectedPromise::GuzzleHttp\Promise{closure}() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/TaskQueue.php:47
GuzzleHttp\Promise\TaskQueue->run() at /home/c2gunstuff/public_html/vendor/guzzlehttp/guzzle/src/Handler/CurlMultiHandler.php:118
GuzzleHttp\Handler\CurlMultiHandler->tick() at /home/c2gunstuff/public_html/vendor/guzzlehttp/guzzle/src/Handler/CurlMultiHandler.php:145
GuzzleHttp\Handler\CurlMultiHandler->execute() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:246
GuzzleHttp\Promise\Promise->invokeWaitFn() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:223
GuzzleHttp\Promise\Promise->waitIfPending() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:267
GuzzleHttp\Promise\Promise->invokeWaitList() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:225
GuzzleHttp\Promise\Promise->waitIfPending() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:267
GuzzleHttp\Promise\Promise->invokeWaitList() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:225
GuzzleHttp\Promise\Promise->waitIfPending() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:62
GuzzleHttp\Promise\Promise->wait() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/EachPromise.php:101
GuzzleHttp\Promise\EachPromise->GuzzleHttp\Promise{closure}() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:246
GuzzleHttp\Promise\Promise->invokeWaitFn() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:223
GuzzleHttp\Promise\Promise->waitIfPending() at /home/c2gunstuff/public_html/vendor/guzzlehttp/promises/src/Promise.php:62
GuzzleHttp\Promise\Promise->wait() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Swiftmailer/Transport/AmazonApiTransport.php:273
Mautic\EmailBundle\Swiftmailer\Transport\AmazonApiTransport->send() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Swiftmailer/Spool/DelegatingSpool.php:75
Mautic\EmailBundle\Swiftmailer\Spool\DelegatingSpool->delegateMessage() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Swiftmailer/Transport/SpoolTransport.php:57
Mautic\EmailBundle\Swiftmailer\Transport\SpoolTransport->send() at /home/c2gunstuff/public_html/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mailer.php:71
Swift_Mailer->send() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Helper/MailHelper.php:431
Mautic\EmailBundle\Helper\MailHelper->send() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Helper/MailHelper.php:613
Mautic\EmailBundle\Helper\MailHelper->flushQueue() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Model/SendEmailToContact.php:118
Mautic\EmailBundle\Model\SendEmailToContact->flush() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Model/SendEmailToContact.php:141
Mautic\EmailBundle\Model\SendEmailToContact->finalFlush() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Model/EmailModel.php:1474
Mautic\EmailBundle\Model\EmailModel->sendEmail() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/Model/EmailModel.php:1089
Mautic\EmailBundle\Model\EmailModel->sendEmailToLists() at /home/c2gunstuff/public_html/app/bundles/EmailBundle/EventListener/BroadcastSubscriber.php:73
Mautic\EmailBundle\EventListener\BroadcastSubscriber->onBroadcast() at /home/c2gunstuff/public_html/vendor/symfony/event-dispatcher/EventDispatcher.php:214
Symfony\Component\EventDispatcher\EventDispatcher->doDispatch() at /home/c2gunstuff/public_html/vendor/symfony/event-dispatcher/EventDispatcher.php:44
Symfony\Component\EventDispatcher\EventDispatcher->dispatch() at /home/c2gunstuff/public_html/app/bundles/ChannelBundle/Command/SendChannelBroadcastCommand.php:101
Mautic\ChannelBundle\Command\SendChannelBroadcastCommand->execute() at /home/c2gunstuff/public_html/vendor/symfony/console/Command/Command.php:255
Symfony\Component\Console\Command\Command->run() at /home/c2gunstuff/public_html/vendor/symfony/console/Application.php:1005
Symfony\Component\Console\Application->doRunCommand() at /home/c2gunstuff/public_html/vendor/symfony/framework-bundle/Console/Application.php:86
Symfony\Bundle\FrameworkBundle\Console\Application->doRunCommand() at /home/c2gunstuff/public_html/vendor/symfony/console/Application.php:255
Symfony\Component\Console\Application->doRun() at /home/c2gunstuff/public_html/vendor/symfony/framework-bundle/Console/Application.php:74
Symfony\Bundle\FrameworkBundle\Console\Application->doRun() at /home/mydirectory/public_html/vendor/symfony/console/Application.php:148
Symfony\Component\Console\Application->run() at /home/c2gunstuff/public_html/bin/console:43

Anyone else experiencing this issue?