Duplicate orders in woocommerce with Braintree

I want to allow duplicate cards however I’m not sure i’m using the filter correctly.

I’m using the following code in a snippet:

add_filter( 'wc_braintree_api_request_data', 'allow_duplicate_card' );
function allow_duplicate_card( $request_data ) {
 if ( isset( $request_data['options'], $request_data['options']['failOnDuplicatePaymentMethod'] ) ) {
  $request_data['options']['failOnDuplicatePaymentMethod'] = false;
  }
 return $request_data;
}

But the hook only seems to fire before I process the payment and when I try to var_dump($request_data) I only get, what looks like, a hashed number so can’t inspect what’s inside that variable.

Any ideas on how to debug this further?