See http://firebearstudio.com/blog/catalog-price-rules-core-bug-in-magento-ce-1-9-1-and-ee-1-14-1-0-array-to-string-conversion-error-and-incorrect-price-rules-behavior.html for further information and a patch So far the issue is still "In progress" on magento bug tracker: http://www.magentocommerce.com/bug-tracking/issue/index/id/278 Is this the kind of things that you'd like to include? What would be the process then?