diff --git a/modules/ppcp-settings/src/Endpoint/OnboardingRestEndpoint.php b/modules/ppcp-settings/src/Endpoint/OnboardingRestEndpoint.php
index 54aced7ef..b055ab3e2 100644
--- a/modules/ppcp-settings/src/Endpoint/OnboardingRestEndpoint.php
+++ b/modules/ppcp-settings/src/Endpoint/OnboardingRestEndpoint.php
@@ -90,7 +90,7 @@ class OnboardingRestEndpoint extends RestEndpoint {
 	public function __construct( OnboardingProfile $profile ) {
 		$this->profile = $profile;
 
-		$this->field_map['products']['sanitize'] = fn( $list ) => array_map( 'sanitize_text_field', $list );
+		$this->field_map['products']['sanitize'] = static fn( $list ) => array_map( 'sanitize_text_field', $list );
 	}
 
 	/**