diff --git a/src/Assignment/AssignmentConfig.php b/src/Assignment/AssignmentConfig.php
index 9275d01..19f3d58 100644
--- a/src/Assignment/AssignmentConfig.php
+++ b/src/Assignment/AssignmentConfig.php
@@ -40,7 +40,7 @@ class AssignmentConfig
     const DEFAULTS = [
         'cacheCapacity' => 65536,
         'minIdLength' => 5,
-        'assignmentFilter' => null,
+        'assignmentFilter' => null
     ];
 
     public function __construct(string $apiKey, int $cacheCapacity, AssignmentTrackingProvider $assignmentTrackingProvider, int $minIdLength,
diff --git a/src/Assignment/AssignmentConfigBuilder.php b/src/Assignment/AssignmentConfigBuilder.php
index fc7907e..8cb0f66 100644
--- a/src/Assignment/AssignmentConfigBuilder.php
+++ b/src/Assignment/AssignmentConfigBuilder.php
@@ -10,7 +10,7 @@ class AssignmentConfigBuilder
     protected AssignmentTrackingProvider $assignmentTrackingProvider;
     protected string $apiKey;
     protected int $minIdLength = AssignmentConfig::DEFAULTS['minIdLength'];
-    protected ?AssignmentFilter $assignmentFilter;
+    protected ?AssignmentFilter $assignmentFilter = AssignmentConfig::DEFAULTS['assignmentFilter'];
 
     public function __construct(string $apiKey, AssignmentTrackingProvider $assignmentTrackingProvider)
     {