LP:881710 - Column name PID returns NULL when called via SP

I have a very simple table like this:

CREATE TABLE `path` (
`PID` int(10) unsigned NOT NULL,
`PPath` varchar(2000) NOT NULL,
`PHash` binary(16) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB;

And a SP:

create procedure test(path VARCHAR(2000))
begin

DECLARE pid INT UNSIGNED;
DECLARE hash BINARY(16) DEFAULT UNHEX(MD5(path));

SELECT PID FROM path LIMIT 1;

end|
call test("/")|

Calling the procedure test() returns NULL. Upper and lower case doesn't matter. Renaming the column to something different like

alter table path change PID id int unsigned;

returns the correct result.