I found a nice new, rarely trigger Magento bug. In one of our projects, we have an example file to create new products: data-upgrade-example-new-product-import.php Beside this we had data scripts: data-install-1.0.1.php data-upgrade-1.0.0-1.0.1.php data-upgrade-1.0.5-1.0.6.php Unfortunately data-upgrade-1.0.