Fix currency submitted on the form

CRM/Core/Payment/MJWTrait.php

@@ -178,6 +178,10 @@ trait CRM_Core_Payment_MJWTrait {
   public function getDefaultCurrencyForForm($form) {
     // For contribution pages it is in $form->_values
     $currency = CRM_Utils_Array::value('currency', $form->_values);
+    if (!$currency && is_a($form, 'CRM_Financial_Form_Payment')) {
+      $currency = $form->getVar('currency');
+    }
+
     if (!$currency) {
       // For event pages it is in $form->_values['event']
       if (isset($form->_values['event'])) {