diff --git a/src/Model/Behavior/UploadBehavior.php b/src/Model/Behavior/UploadBehavior.php
index 946367b..8de4527 100644
--- a/src/Model/Behavior/UploadBehavior.php
+++ b/src/Model/Behavior/UploadBehavior.php
@@ -37,6 +37,8 @@ class UploadBehavior extends Behavior
      */
     public function initialize(array $config): void
     {
+        unset($config['className']);
+
         $configs = [];
         foreach ($config as $field => $settings) {
             if (is_int($field)) {
@@ -46,8 +48,7 @@ public function initialize(array $config): void
             }
         }
 
-        $this->setConfig($configs);
-        $this->setConfig('className', null);
+        $this->setConfig($configs, null, false);
 
         $schema = $this->_table->getSchema();
         /** @var string $field */
diff --git a/tests/TestCase/Model/Behavior/UploadBehaviorTest.php b/tests/TestCase/Model/Behavior/UploadBehaviorTest.php
index b7e9f45..d341e31 100644
--- a/tests/TestCase/Model/Behavior/UploadBehaviorTest.php
+++ b/tests/TestCase/Model/Behavior/UploadBehaviorTest.php
@@ -743,13 +743,13 @@ public function testNameCallback()
         $table = $this->getTableLocator()->get('Files');
         $behavior = new ChildBehavior($table, [
             'filename' => [
-                'nameCallback' => function ($table, $entity, $data, $field, $settings) {
-                    return 'Awesome Filename.png';
-                },
+                'nameCallback' => [$this, 'nameCallback'],
                 'transformer' => SlugTransformer::class,
             ],
         ]);
 
+        $this->assertSame([$this, 'nameCallback'], $behavior->getConfig('filename.nameCallback'));
+
         $event = new Event('Model.beforeSave', $table);
         $entity = new Entity([
             'filename' => $this->dataOk['field'],
@@ -763,4 +763,9 @@ public function testNameCallback()
 
         $this->assertEquals($expected, $behavior->constructedFiles);
     }
+
+    public function nameCallback($table, $entity, $data, $field, $settings)
+    {
+        return 'Awesome Filename.png';
+    }
 }