WooCommerce was updated to version 2.3.3, from version 2.3.2. Changelog:

• Fix – Potential notice with preg_match wildcard search, if used incorrectly.
• Fix – Typo in get_from_name method.
• Fix – Fix errors during checkout when mb_convert_encoding() is not supported.
• Fix – Change hooks used to output post columns – fixes columns after quick edit.
• Fix – Only apply product/cat coupon checks for cart to cart coupons.
• Fix – Query in uninstall script.
• Tweak – Only run the uninstaller if the “Uninstall on Delete” option is checked in system status.