"1062 Duplicate entry" on SELECT - mysql

Question

I've got a SELECT query that's returning the following error:
SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'user_id-name email#address.com--2018-11-04 01:24:38' for key ''
(I replaced the user_id, name and email for privacy)
SELECT users.user_id, users.fullname, users.email, users.phone_formatted, users.date_created,
MAX(cards.card_id) AS latest_card_id, MAX(cards.date_created) AS latest_date_card, MAX(punches.date_created) AS date_lastvisited
FROM users
INNER JOIN cards ON cards.user_id = users.user_id
INNER JOIN punches ON punches.card_id = cards.card_id
WHERE punches.business_id=1626
GROUP BY users.user_id, users.fullname, users.email, users.phone_formatted, users.date_created
ORDER BY users.fullname;
Here are the table definitions for cards, punches and users:
CREATE TABLE `cards` (
`card_id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) DEFAULT NULL,
`business_id` int(11) DEFAULT NULL,
`printjob_id` int(11) DEFAULT NULL,
`temp` varchar(256) DEFAULT NULL,
`active` tinyint(1) NOT NULL DEFAULT '1',
`whitelabel_id` int(11) NOT NULL DEFAULT '0',
`date_created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`card_id`),
KEY `printjob_id` (`printjob_id`),
KEY `active` (`active`),
KEY `user_id` (`user_id`),
KEY `business_id` (`business_id`)
) ENGINE=InnoDB AUTO_INCREMENT=576475 DEFAULT CHARSET=latin1;
CREATE TABLE `punches` (
`punch_id` int(11) NOT NULL AUTO_INCREMENT,
`punch_count` int(11) unsigned NOT NULL DEFAULT '1',
`employeebonus` tinyint(1) NOT NULL DEFAULT '0',
`details` text,
`card_id` int(11) DEFAULT NULL,
`behaviour` set('basicpunch','employeebonus','visitsregularly','broughtfriend','mytreat','firstcustomer','dailyrepeater','visitslocations','facebookshare','mostfrequent','longabsence','registerer','employeepromoter','luckiest','enroll','opportunist') NOT NULL DEFAULT 'basicpunch',
`location_id` int(11) DEFAULT NULL,
`business_id` int(11) DEFAULT NULL,
`employee_id` int(11) DEFAULT NULL,
`v1` float DEFAULT NULL,
`eventcounter` smallint(5) unsigned NOT NULL DEFAULT '0',
`date_local` timestamp NULL DEFAULT CURRENT_TIMESTAMP,
`date_created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`punch_id`),
KEY `business_id` (`business_id`),
KEY `employee_id` (`employee_id`),
KEY `card_id` (`card_id`),
KEY `date_created` (`date_created`),
KEY `behaviour_id` (`behaviour`),
KEY `location_id` (`location_id`),
KEY `employeebonus` (`employeebonus`),
KEY `punch_count` (`punch_count`)
) ENGINE=InnoDB AUTO_INCREMENT=807402 DEFAULT CHARSET=latin1;
CREATE TABLE `users` (
`user_id` int(11) NOT NULL AUTO_INCREMENT,
`fullname` varchar(60) DEFAULT NULL,
`email` varchar(50) NOT NULL,
`undeliverable` tinyint(4) DEFAULT '0',
`phone_formatted` varchar(25) DEFAULT NULL,
`phone_unformatted` varchar(15) DEFAULT NULL,
`password_hash` char(64) DEFAULT NULL,
`password_salt` char(6) DEFAULT NULL,
`reset_hash` binary(32) DEFAULT NULL,
`date_reset` datetime DEFAULT NULL,
`stripecustomer_id` int(11) DEFAULT NULL,
`stripe_customer_id` varchar(40) DEFAULT NULL,
`stripe_customer_access_id` varchar(40) DEFAULT NULL,
`problemwithpayment` tinyint(1) NOT NULL DEFAULT '0',
`enterprisemanager_whitelabel_id` int(11) NOT NULL DEFAULT '0',
`god` tinyint(1) NOT NULL DEFAULT '0',
`date_created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`user_id`),
KEY `email` (`email`),
KEY `phone_unformatted` (`phone_unformatted`),
KEY `date_reset` (`date_reset`),
KEY `undeliverable` (`undeliverable`)
) ENGINE=InnoDB AUTO_INCREMENT=16809 DEFAULT CHARSET=latin1;
I don't understand how I can get this error with a SELECT query. When I remove the MAX() functions, I no longer get the error.