diff --git a/src/Services/QueuedJobHandler.php b/src/Services/QueuedJobHandler.php
index 316948e2..c8958cf9 100644
--- a/src/Services/QueuedJobHandler.php
+++ b/src/Services/QueuedJobHandler.php
@@ -4,6 +4,7 @@
 
 use Monolog\Handler\AbstractProcessingHandler;
 use SilverStripe\Core\Injector\Injectable;
+use SilverStripe\ORM\DB;
 use Symbiote\QueuedJobs\DataObjects\QueuedJobDescriptor;
 
 /**
@@ -56,6 +57,12 @@ protected function write(array $record)
 
     public function handleBatch(array $records)
     {
+        // Guard against handlers auto-flushing on destruct.
+        // When this is part of a PHPUnit run, the connection to the database can have already been closed.
+        if (!DB::is_active()) {
+            return;
+        }
+
         foreach ($records as $record) {
             $this->job->addMessage($record['message'], $record['level_name'], $record['datetime']);
         };