pt-online-schema-change doesn't recognize fields in alter if the are using Upercase chars

CREATE TABLE `mydb`.`t1` (
`c1` int(10) unsigned NOT NULL,
`c2` varchar(255) NOT NULL,
`Last_referenced` datetime NOT NULL,
`c3` int(10) unsigned NOT NULL,
`c4` int(10) unsigned NOT NULL DEFAULT '0',
`c5` varchar(255) NOT NULL DEFAULT '',
`c6` varchar(255) NOT NULL DEFAULT '',
`c7` varchar(255) NOT NULL DEFAULT '',
`c8` varchar(255) DEFAULT '',
`c9` varchar(255) DEFAULT '',
`c10` int(10) NOT NULL DEFAULT '0',
PRIMARY KEY (`c1`,`c2`),
KEY `Last_Referenced_c6_Index` (`Last_referenced`,`c6`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1

pt-online-schema-change --alter 'CHANGE COLUMN `Last_referenced` `c11` datetime NOT NULL' --ask-pass --noswap-tables --nodrop-triggers --chunk-time 0.1 --nodrop-new-table --no-check-alter --execute D=mydb,t=t1,h=mydbhost,P=3306