Uploaded Resume's Corrupted

[WRS]

I've got an odd issue. The uploaded resumes are being corrupted. It started out of the blue a little over a month ago. I believe the issue is related to how they're stored in MySQL, but I'm not sure. When I upload text resume, everything works perfectly. In every case, all the other fields are fine.

When I upload a binary resume, say, pdf for instance, when downloaded, it can't be read. It was working until the end of december, then it started to have this problem. The table structure looks correct, and I tried dumping / applying it.

Here's the structure:
CREATE TABLE `hs_hr_job_application` (
`application_id` int(11) NOT NULL,
`vacancy_id` int(11) NOT NULL,
`lastname` varchar(100) NOT NULL DEFAULT '',
`firstname` varchar(100) NOT NULL DEFAULT '',
`middlename` varchar(100) NOT NULL DEFAULT '',
`street1` varchar(100) DEFAULT '',
`street2` varchar(100) DEFAULT '',
`city` varchar(100) DEFAULT '',
`country_code` varchar(100) DEFAULT '',
`province` varchar(100) DEFAULT '',
`zip` varchar(20) DEFAULT NULL,
`phone` varchar(50) DEFAULT NULL,
`mobile` varchar(50) DEFAULT NULL,
`email` varchar(50) DEFAULT NULL,
`qualifications` text,
`status` smallint(2) DEFAULT '0',
`applied_datetime` datetime DEFAULT NULL,
`emp_number` int(7) DEFAULT NULL,
`resume_name` varchar(100) DEFAULT NULL,
`resume_data` mediumblob,
PRIMARY KEY (`application_id`),
KEY `vacancy_id` (`vacancy_id`),
CONSTRAINT `hs_hr_job_application_ibfk_1` FOREIGN KEY (`vacancy_id`) REFERENCES `hs_hr_job_vacancy` (`vacancy_id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

I don't believe there was any change to the database configuration or php in that time. Looking at the data, most of it, of course, it unreadable on the console, but pdf's contain text headers and footers, and those are identical to what I get from opening the pdf in a text editor, so the data is getting there at least. (though the binary part of it may be mangled)

Anyone have any clues as to where I could look to track this down?