File uploading error in codeception?

I'm trying to upload the file to the couple of input elements. The id attributes of these inputs are always generated randomly, so I receive a list of RemoteWebElements from my helper function:

function getInputFields() {
    $inputs = $this->getModule('WebDriver')->_findElements(['xpath' => "//input[@type='file']"]);
    return $inputs;
 }

Then, in the Cept I'm trying to upload the file, inserting the ID to XPath string

$pass = $I->getInputFields();
$path_to_input1 = "//*[@id='" . $pass[0]->getAttribute('id') ."']";
$I->attachFile($path_to_input1, '1.jpg');

I'm pretty sure that input element exists, and I get its ID correctly, checked by debug output. And getting this:

[ERROR - 2015-08-28T11:15:35.801Z] RouterReqHand - _handle.error - {"stack":"\tat _uploadFile ([native code])\n\tat \n\tat _postUploadFileCommand (:/ghostdriver/request_handlers/session_request_handler.js:212:30)\n\tat _handle (:/ghostdriver/request_handlers/session_request_handler.js:198:35)\n\tat _reroute (:/ghostdriver/request_handlers/request_handler.js:61:20)\n\tat _handle (:/ghostdriver/request_handlers/router_request_handler.js:78:46)","line":431,"sourceURL":""}

[Facebook\WebDriver\Exception\WebDriverException] JSON decoding of remote response failed.
Error code: 4
The response: 'Error - incompatible type of argument(s) in call to _uploadFile(); candidates were
_uploadFile(QString,QStringList)'

Can you please help me, where is the pitfall here?